98401.	What should come in place of the question mark '?' in the following number series?4, 23, 114, ?, 13641. 4552. 6553. 1454. 234
Answer» Correct Answer - Option 1 : 455 The series follows the following pattern: 4 × 6 – 1 = 23 23 × 5 – 1 = 114 114 × 4 – 1 = 455 455 × 3 – 1 = 1364 ∴ The missing number is 455

What should come in place of the question mark '?' in the following number series?4, 23, 114, ?, 13641. 4552. 6553. 1454. 234

Answer» Correct Answer - Option 1 : 455

The series follows the following pattern:

4 × 6 – 1 = 23

23 × 5 – 1 = 114

114 × 4 – 1 = 455

455 × 3 – 1 = 1364

∴ The missing number is 455

Discussion

98402.	What should come in place of the question mark '?' in the following number series?3, 5, 8, 12, ?, 231. 222. 173. 134. 155. 14
Answer» Correct Answer - Option 2 : 17 Calculation∶ The series follows following pattern ⇒ 3 + 2 = 5 ⇒ 5 + 3 = 8 ⇒ 8 + 4 = 12 ⇒ 12 + 5 = 17 ⇒ 17 + 6 = 23 ∴ The value of ? is 17

98402.

What should come in place of the question mark '?' in the following number series?3, 5, 8, 12, ?, 231. 222. 173. 134. 155. 14

Answer» Correct Answer - Option 2 : 17

Calculation∶

The series follows following pattern

⇒ 3 + 2 = 5

⇒ 5 + 3 = 8

⇒ 8 + 4 = 12

⇒ 12 + 5 = 17

⇒ 17 + 6 = 23

∴ The value of ? is 17

Discussion

98403.	Frenkel defect and Schottky defect
Answer» Schottky defect: Schottky defect or small shot effect is named after a popular German physicist Walter H. In his model, he explains that the defect is formed in ionic crystals when oppositely charged ions leave their lattice sites which leads to the creation of vacancies. These vacancies are further created to maintain a neutral charge in the crystal. The model further explains that the surrounding atoms also move to occupy these vacancies. Typically, when the defect is found in non-ionic crystals it is referred to as lattice vacancy defect. Definition: Schottky defect is a type of point defect or imperfection in solids which is caused by a vacant position that is generated in a crystal lattice due to the atoms or ions moving out from the interior to the surface of the crystal. Frenkel defect Yakov Frenkel, a Russian physicist was the person who discovered the Frenkel defect while conducting research on the molecular theory of the condensed state. This discovery was important as his model explained a defect in the molecule of crystalline solids where an atom or ion moved out of their own lattice site making it vacant while occupying another intermediary vacant site on the same crystal. The defect is also known as dislocation defect and it also clearly depicts both vacancy and self-interstitial defects. Definition: A Frenkel defect is another form of a point defect which is created when an atom or cation leaves its original place in the lattice structure to create a vacancy while occupying another interstitial position within the solid crystal.

98403.

Frenkel defect and Schottky defect

Answer»

Schottky defect:

Schottky defect or small shot effect is named after a popular German physicist Walter H. In his model, he explains that the defect is formed in ionic crystals when oppositely charged ions leave their lattice sites which leads to the creation of vacancies. These vacancies are further created to maintain a neutral charge in the crystal. The model further explains that the surrounding atoms also move to occupy these vacancies. Typically, when the defect is found in non-ionic crystals it is referred to as lattice vacancy defect.

Definition: Schottky defect is a type of point defect or imperfection in solids which is caused by a vacant position that is generated in a crystal lattice due to the atoms or ions moving out from the interior to the surface of the crystal.

Frenkel defect

Yakov Frenkel, a Russian physicist was the person who discovered the Frenkel defect while conducting research on the molecular theory of the condensed state. This discovery was important as his model explained a defect in the molecule of crystalline solids where an atom or ion moved out of their own lattice site making it vacant while occupying another intermediary vacant site on the same crystal. The defect is also known as dislocation defect and it also clearly depicts both vacancy and self-interstitial defects.

Definition: A Frenkel defect is another form of a point defect which is created when an atom or cation leaves its original place in the lattice structure to create a vacancy while occupying another interstitial position within the solid crystal.

Discussion

98404.	One male of nitrogen gas at `0.8` atm takes 38 seconds on diffuse through a pinhole, whereas one mole of a compound of xenon with fluorine at 1.6 atm takes 57 secondes to diffuse through the same hole. Calculate molecular weight of the compound.
Answer» Correct Answer - `00252.00` `00252.00` `(r_(1))/(r_(2))=sqrt((M_(2))/(M_(1)))xx(P_(1))/(P_(2))` or `(n_(1))/(t_(1))xx(t_(2))/(n_(2))=sqrt((M_(2))/(M_(1)))xx(P_(1))/(P_(2))` or `1/38xx57/1=sqrt(M/28)xx0.8/1.6` `:. M=252`

Discussion

98405.	Which among the following is a basic amino acid? (A) Aspargine (B) Arginine (C) Proline (D) Alanine
Answer» Answer: (B) Arginine

Discussion

98406.	Chemical Reactions and Equations Notes Class 10 for revision
Answer» Chemical Reactions and Equations: In our day to day life, we see several chemical changes take place. To study these changes scientists classified it in different types of chemical reactions. In this section, we will read chemical reactions and equations notes for class 10. Read and learn it pointwise. Chemical reaction: Whenever a chemical change occurs it is said to be chemical reaction. The process in which new substances with new properties are formed from one or more substances is called Chemical Reaction. Eg. Rusting of Iron, Burning of wood Formation of Curd Respiration etc. Following observations help to determine whether a chemical reaction has taken place: Change in state Change in colour Evolution of a gas Change in temperature Reactant: The substances which take part in chemical reaction. Product: The substances which are formed in a chemical reaction. Chemical Equation: Symbolic representation of a chemical reaction is said to be Chemical equation. It involves uses of symbol of elements or chemical formula of reactant and product with mention of physical state. The necessary conditions such as temperature, pressure or any catalyst should be written on arrow between reactant and products. Eg. Magnesium is burnt into air to form magnesium oxide can be represented as Mg + O2 →MgO (Physical state of the reactant and products are mentioned to make chemical reaction more informative. eg we use (g) for gas, (l) for liquid, (s) for solid and (aq) for aqueous. Thus is good for chemical reactions and equations notes) Balancing Chemical Equation: Chemical reactions and equations notes also include the mean to balance the equations by several methods. They are: Law of Conservation of Mass: Mass can neither be created nor be destroyed in a chemical reaction. Thus remains conserved. So number of elements involved in product side will be same as reactant side. Eg. H₂+O₂→H₂O In this Chemical equation number of H atoms in reactant side is 2 and that of product side is also 2. Number of O atoms in reactant side is 2 but that of product side is 1. To balance this equation we have to use hit and trial method. 2H₂+O₂→2H₂O Now the number of atoms in reactant side is equal to that of product side. Thus, balanced. Now, we will read types on the basis of various factors in chemical reactions and equations notes. Types of Chemical Reactions: There are several types of chemical reaction based on different factors. However, in chemical reactions and equations notes some of them are mentioned as: Classification of Chemical Reactions based on Chemical Change: Combination Reaction: The reaction in which two or more substances combine to form a new single substance. Eg. C_(s) + O_2(g) →CO_2(g) Decomposition reaction: The reaction in which a single substance decomposes to give two or more substances. A → B + C Decomposition reactions can be of three types: Thermal Decomposition: When a decomposition reaction is carried out by heating. Eg. CaCO3 (s) → CaO (s) + CO₂ (g) (calcium carbonate) (quick lime) (carbon dioxide) Electrolytic Decomposition : When decomposition is carried out by passing electricity. *e.g., 2H₂O + electric current* → 2H₂ + O₂ Photolytic Decomposition : When decomposition is carried out in presence of sunlight. *e.g., 2AgCl (s) + sunlight→2Ag (s) + Cl₂ (g) Displacement Reaction:* The chemical Reaction in which an element displaces another element from its solution. Eg. Fe(s) + CuSO₄(aq) → FeSO₄ + Cu(s) Double Displacement Reaction: The reaction in which two different atoms or group of atoms are mutually exchanged. Eg. Na₂SO₄ + BaCl₂ → BaSO_4(s) + 2NaCl Precipitation reaction: The reaction which involves formation of precipitate (insoluble substance) is known as precipitation reaction. Eg. Pb(NO₃)₂(aq) + 2KI(aq) → 2KNO₃(aq) + PbI₂(s) Oxidation reaction: The reaction in which substance gains oxygen or loses hydrogen is called as oxidation reaction. Eg. 2Cu(s) + O₂(g)+ Heat → 2CuO(s) Reduction reaction: The reaction in which substance gains hydrogen or loses oxygen is called as reduction reaction. Eg. C(s) + 2H₂(g) → CH₄(g) Oxidation-reduction reaction (Redox reaction):The reaction in which one reactant gets oxidised and the other reactant gets reduced is called as oxidation-reduction reaction or redox reaction. In this reaction, simultaneous oxidation and reduction reactions take place. Eg. ZnO + C → Zn + CO MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂ Classification of chemical reactions based on energy change: The classification of reactions is the prime part of chemical reactions and equations notes: Exothermic Reactions: Reaction in which heat is released along with formation of products. Eg. CH_4(g) + 2O_2(g) → CO_2(g) + 2H₂O_(g) + Heat Endothermic reactions: The reactions which require energy in the form of heat, light or electricity to break reactants are called endothermic reactions. Eg. 2Pb(NO₃)_2(s) 2PbO_(s) + 4NO_2(g) + O_2(g) Effects of Oxidation in Daily Life: We read chemical reactions and equations notes to understand mechanisms and process by which changes take place. Some instances are: 1) Corrosion When a metal is exposed to substances such as moisture, acid etc. for some time, a layer of hydrated oxide is formed which weakens the metal and hence metal is said to be corrode Rusting of iron, black coating on silver and green coating on copper are examples of corrosion. Corrosion can be prevented by galvanization, electroplating or painting. 2) Rancidity: The oxidation of fats and oils when exposed to air is known as rancidity. It leads to bad smell and bad taste of food. Methods to Prevent Rancidity By adding antioxidants Keeping food in airtight containers Replacing air by nitrogen Refrigeration NCERT class 10 chemistry chapter 1 notes is here with all the key points which will make your concepts clear. Learn chemical reactions and equations notes with precise definitions and types. More notes are mentioned in class 10 science notes.

98406.

Chemical Reactions and Equations Notes Class 10 for revision

Answer»

Chemical Reactions and Equations:

In our day to day life, we see several chemical changes take place. To study these changes scientists classified it in different types of chemical reactions. In this section, we will read chemical reactions and equations notes for class 10. Read and learn it pointwise.

Chemical reaction:

Whenever a chemical change occurs it is said to be chemical reaction.
The process in which new substances with new properties are formed from one or more substances is called Chemical Reaction.

Eg.

Rusting of Iron,
Burning of wood
Formation of Curd
Respiration etc.

Following observations help to determine whether a chemical reaction has taken place:

Change in state
Change in colour
Evolution of a gas
Change in temperature

Reactant: The substances which take part in chemical reaction.

Product: The substances which are formed in a chemical reaction.

Chemical Equation:

Symbolic representation of a chemical reaction is said to be Chemical equation.
It involves uses of symbol of elements or chemical formula of reactant and product with mention of physical state.
The necessary conditions such as temperature, pressure or any catalyst should be written on arrow between reactant and products.
Eg. Magnesium is burnt into air to form magnesium oxide can be represented as
Mg + O2 →MgO

(Physical state of the reactant and products are mentioned to make chemical reaction more informative. eg we use (g) for gas, (l) for liquid, (s) for solid and (aq) for aqueous. Thus is good for chemical reactions and equations notes)

Balancing Chemical Equation:

Chemical reactions and equations notes also include the mean to balance the equations by several methods. They are:

Law of Conservation of Mass:

Mass can neither be created nor be destroyed in a chemical reaction. Thus remains conserved.
So number of elements involved in product side will be same as reactant side.
Eg. H₂+O₂→H₂O
In this Chemical equation number of H atoms in reactant side is 2 and that of product side is also 2. Number of O atoms in reactant side is 2 but that of product side is 1.
To balance this equation we have to use hit and trial method.
2H₂+O₂→2H₂O
Now the number of atoms in reactant side is equal to that of product side. Thus, balanced.
Now, we will read types on the basis of various factors in chemical reactions and equations notes.

Types of Chemical Reactions:

There are several types of chemical reaction based on different factors. However, in chemical reactions and equations notes some of them are mentioned as:

Classification of Chemical Reactions based on Chemical Change:

Combination Reaction: The reaction in which two or more substances combine to form a new single substance.
Eg. C_(s) + O_2(g) →CO_2(g)

Decomposition reaction: The reaction in which a single substance decomposes to give two or more substances.
A → B + C

Decomposition reactions can be of three types:

Thermal Decomposition: When a decomposition reaction is carried out by heating.
Eg. CaCO3 (s) → CaO (s) + CO₂ (g)
(calcium carbonate) (quick lime) (carbon dioxide)

Electrolytic Decomposition : When decomposition is carried out by passing electricity.
e.g., 2H₂O + electric current → 2H₂ + O₂

Photolytic Decomposition : When decomposition is carried out in presence of sunlight.
e.g., 2AgCl (s) + sunlight→2Ag (s) + Cl₂ (g)

Displacement Reaction: The chemical Reaction in which an element displaces another element from its solution.
Eg. Fe(s) + CuSO₄(aq) → FeSO₄ + Cu(s)

Double Displacement Reaction: The reaction in which two different atoms or group of atoms are mutually exchanged.
Eg. Na₂SO₄ + BaCl₂ → BaSO_4(s) + 2NaCl

Precipitation reaction: The reaction which involves formation of precipitate (insoluble substance) is known as precipitation reaction.
Eg. Pb(NO₃)₂(aq) + 2KI(aq) → 2KNO₃(aq) + PbI₂(s)

Oxidation reaction: The reaction in which substance gains oxygen or loses hydrogen is called as oxidation reaction.
Eg. 2Cu(s) + O₂(g)+ Heat → 2CuO(s)

Reduction reaction: The reaction in which substance gains hydrogen or loses oxygen is called as reduction reaction.
Eg. C(s) + 2H₂(g) → CH₄(g)

Oxidation-reduction reaction (Redox reaction):The reaction in which one reactant gets oxidised and the other reactant gets reduced is called as oxidation-reduction reaction or redox reaction. In this reaction, simultaneous oxidation and reduction reactions take place.
Eg. ZnO + C → Zn + CO
MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂

Classification of chemical reactions based on energy change:

The classification of reactions is the prime part of chemical reactions and equations notes:

Exothermic Reactions: Reaction in which heat is released along with formation of products.
Eg. CH_4(g) + 2O_2(g) → CO_2(g) + 2H₂O_(g) + Heat

Endothermic reactions: The reactions which require energy in the form of heat, light or electricity to break reactants are called endothermic reactions.
Eg. 2Pb(NO₃)_2(s) 2PbO_(s) + 4NO_2(g) + O_2(g)

Effects of Oxidation in Daily Life:

We read chemical reactions and equations notes to understand mechanisms and process by which changes take place. Some instances are:

1) Corrosion

When a metal is exposed to substances such as moisture, acid etc. for some time, a layer of hydrated oxide is formed which weakens the metal and hence metal is said to be corrode
Rusting of iron, black coating on silver and green coating on copper are examples of corrosion.
Corrosion can be prevented by galvanization, electroplating or painting.

2) Rancidity: The oxidation of fats and oils when exposed to air is known as rancidity. It leads to bad smell and bad taste of food.

Methods to Prevent Rancidity

By adding antioxidants
Keeping food in airtight containers
Replacing air by nitrogen
Refrigeration

NCERT class 10 chemistry chapter 1 notes is here with all the key points which will make your concepts clear. Learn chemical reactions and equations notes with precise definitions and types. More notes are mentioned in class 10 science notes.

Discussion

98407.	The first `(Delta_(i)H_(1))` and second `(Delta_(i)H_(2))` ionisation enthalpies `("in" kJ mol^(-1))` and the `(Delta_(eg)H^(ө))` electron gain enthalpy `("in" kJ mol^(-1))` of a few elements are given below: `{:("Elements",(Delta_(i)H_(1)),(Delta_(i)H_(2)),Delta_(eg)H^(ө)),(I,520,7300,-60),(II,419,3051,-48),(III,1681,3374,-328),(IV,1008,1846,-295),(V,2372,5251,+48),(VI,738,1451,-40):}` Which of the above elements is likely to be a. the least reactive element. b. the most reactive metal. c. the most reactive non-metal. d. the least reactive non-metal. e. the metal which can form a stable binary halide of the formula MX2 (X=halogen). f. the metal which can form a predominantly stable covalent halide of the formula MX(X=halogen).A. RB. SC. PD. U
Answer» Correct Answer - A Non-metal having higher negative value of electron gain enthalpy corresponds to halogen.Hence R is more reactive non-metal (easily forms anion)

Discussion

98408.	The first `(Delta_IH_1)` and second `(Delta_IH_2)` ionisation enthalpies (in kJ `"mol"^(-1)`) and the `(Delta_(eg)H)` electron gain enthalpy (in kJ `"mol"^(-1)`) of a few elements are given below: The least reactive element is :A. PB. QC. RD. T
Answer» Correct Answer - D Value corresponds to noble gases.Hence , T is inert toward chemical reactivity.

Discussion

98409.	What is the basis of the radius ratio theory?
Answer» Radius Ratio Rule Relation between the radius, co-ordination number and the structural arrangement of the molecule. Radius ratio = Radius of cation(r⁺)/Radius of anion(r^-) Greater the radius ratio, larger the size of the cation and hence the co-ordination number.

98409.

What is the basis of the radius ratio theory?

Answer»

Radius Ratio Rule

Relation between the radius, co-ordination number and the structural arrangement of the molecule.

Radius ratio = Radius of cation(r⁺)/Radius of anion(r^-)

Greater the radius ratio, larger the size of the cation and hence the co-ordination number.

Discussion

98410.	What is buffer solution? Give an example and discuss its activities.
Answer» A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added. A solution of acetic acid and sodium acetate (CH₃COOH + CH₃COONa) is an example of a buffer that consists of a weak acid and its salt. An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride (NH₃(aq) + NH₄Cl(aq)).

98410.

What is buffer solution? Give an example and discuss its activities.

Answer»

A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added.

A solution of acetic acid and sodium acetate (CH₃COOH + CH₃COONa) is an example of a buffer that consists of a weak acid and its salt.

An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride (NH₃(aq) + NH₄Cl(aq)).

Discussion

98411.	Fluorine has the highest electronegativity among the group on the Pauling scale, but the electron affinity of fluorine is less than that of chlorine becauseA. The atomic number of fluorine is less than that of chlorineB. Fluorine being the first member of the family behaves in an unuseual mannerC. Chlorine can accommodate an electron better than fluorine by untilising its vacant `3d` orbitalD. Small size, high electron density and an increases electron repulsion make addition of an electron to fluorine less favourable than that in the case of chlorine
Answer» Correct Answer - D

Discussion

98412.	If measured value of resistance `R = 1.05Omega` wire diameter `d = 0.60 mm` and length `l = 75.3 cm` If maximum error in resistance measurment is `0.01 Omega` and least count of diameter and length measuring device are `0.01 mm` and `0.1cm` respectively then find max permissible error in resistiviry `rho=(R((pid^(2))/(4)))/(l)` .
Answer» `((Deltarho)/(rho))_(max)=(DeltaR)/(R)+2(Deltad)/(d)+(Deltal)/(l)` `DeltaR = 0.01 Omega` `Deltad = 0.01 mm` (least count) `Deltal = 0.1 cm` (least count) `((Deltarho)/(rho))_(max)=((0.01Omega)/(1.05Omega)+2(0.01mm)/(0.60mm)+(0.1cm)/(75.3cm))xx100=4.3%` .

Discussion

98413.	Below what temperature, a gas does not obey ideal gas laws?
Answer» Below Boyle’s Temperature.

Discussion

98414.	The correct option with respect to the Pauling electronegativity values of the elements is : (1) Ga < Ge(2) Te > Se(3) Si < Al(4) P > S
Answer» Correct option (1) Ga < Ge Explanation: As we move left to Right, Electronegativity increases. Si > Al ; S > P ; Ge > Ga. As we move top to bottom; electronegativity decreases. Se > Te.

98414.

The correct option with respect to the Pauling electronegativity values of the elements is : (1) Ga < Ge(2) Te > Se(3) Si < Al(4) P > S

Answer»

Correct option (1) Ga < Ge

Explanation:

As we move left to Right, Electronegativity increases.

Si > Al ; S > P ; Ge > Ga.

As we move top to bottom; electronegativity decreases.

Se > Te.

Discussion

98415.	The metal used for making X-ray tube window is : (1) Mg (2) Na (3) Ca (4) Be
Answer» Correct option: (4) Be Explanation: Metallic beryllium is used for making windows of x-ray tubes.

98415.

The metal used for making X-ray tube window is : (1) Mg (2) Na (3) Ca (4) Be

Answer»

Correct option: (4) Be

Explanation:

Metallic beryllium is used for making windows of x-ray tubes.

Discussion

98416.	The pair that has similar atomic radii is : (1) Mo and W (2) Mn and Re (3) Ti and Hf (4) Sc and Ni
Answer» Correct option (1) Mo and W Explanation: Sol. Size of 3d < 4d = 5d (due to lanthanoid contraction) So, size M0 ≅ W

98416.

The pair that has similar atomic radii is : (1) Mo and W (2) Mn and Re (3) Ti and Hf (4) Sc and Ni

Answer»

Correct option (1) Mo and W

Explanation:

Sol. Size of 3d < 4d = 5d (due to lanthanoid contraction)

So, size M0 ≅ W

Discussion

98417.	What is common ion effect? Give an example.
Answer» Suspension of degree of dissociation of weak electrolyte by the addition of strong electrolyte having a common ion is called common ion effect.

Discussion

98418.	The upper stratosphere consisting of the ozone layer protects us from the sun's radiation that falls in the wavelength region of : (1) 600 – 750 nm (2) 0.8 – 1.5 nm (3) 400 – 550 nm (4) 200 – 315 nm
Answer» Correct option: (4) 200 – 315 nm Explanation: The upper stratosphere consists of considerable amount of ozone (O₃), which protects us from the harmful ultraviolet (UV) radiations (λ = 255 nm) coming from the sun.

98418.

The upper stratosphere consisting of the ozone layer protects us from the sun's radiation that falls in the wavelength region of : (1) 600 – 750 nm (2) 0.8 – 1.5 nm (3) 400 – 550 nm (4) 200 – 315 nm

Answer»

Correct option: (4) 200 – 315 nm

Explanation:

The upper stratosphere consists of considerable amount of ozone (O₃), which protects us from the harmful ultraviolet (UV) radiations (λ = 255 nm) coming from the sun.

Discussion

98419.	The correct order of atomic radii is : (1) Ce > Eu > Ho > N (2) Eu > Ce > Ho > N (3) Ho > N > Eu > Ce (4) N > Ce > Eu > Ho
Answer» Correct option: (2) Eu > Ce > Ho > N Explanation: Atomic radic gradually decrease along the series. If we consider the atomic (i.e., metallic) radii for the lanthanides, two peaks appear at (₆₃Eu [Xe] 4f⁷ 5d⁰ 6s²) and ₇₀Yb [Xe] 4f¹⁴ 5d⁰ 6s². Eu and Yb each can provide only 2 electrons for metallic bonding while the other members each can provide 3e^– for the bonding purpose.

98419.

The correct order of atomic radii is : (1) Ce > Eu > Ho > N (2) Eu > Ce > Ho > N (3) Ho > N > Eu > Ce (4) N > Ce > Eu > Ho

Answer»

Correct option: (2) Eu > Ce > Ho > N

Explanation:

Atomic radic gradually decrease along the series. If we consider the atomic (i.e., metallic) radii for the lanthanides, two peaks appear at (₆₃Eu [Xe] 4f⁷ 5d⁰ 6s²) and ₇₀Yb [Xe] 4f¹⁴ 5d⁰ 6s².

Eu and Yb each can provide only 2 electrons for metallic bonding while the other members each can provide 3e^– for the bonding purpose.

Discussion

98420.	Identify the two conjugate acid base pairs in the following NH3 + HCl ⇌ NH4+ + Cl–
Answer» NH₃ / NH₄⁺, HCl / Cl^–

Discussion

98421.	The correct order for acid strength of compounds :CH ≡ CH, CH3 – C ≡ CH and CH2 = CH2 is as follows : (1) CH3 – C ≡ CH > CH2 = CH2 > HC ≡ CH (2) CH ≡ CH > CH2 = CH2 > CH3 – C ≡ CH (3) CH3 – C ≡ CH > CH ≡ CH > CH2 = CH2 (4) HC ≡ CH > CH3 – C ≡ CH > CH2 = CH2
Answer» The correct option (4) HC ≡ CH > CH₃ – C ≡ CH > CH₂ = CH₂ Explanation: HC ≡ CH > CH₃ – C ≡ CH > CH₂ = CH₂ Acidic strength order.

98421.

The correct order for acid strength of compounds :CH ≡ CH, CH3 – C ≡ CH and CH2 = CH2 is as follows : (1) CH3 – C ≡ CH > CH2 = CH2 > HC ≡ CH (2) CH ≡ CH > CH2 = CH2 > CH3 – C ≡ CH (3) CH3 – C ≡ CH > CH ≡ CH > CH2 = CH2 (4) HC ≡ CH > CH3 – C ≡ CH > CH2 = CH2

Answer»

The correct option (4) HC ≡ CH > CH₃ – C ≡ CH > CH₂ = CH₂

Explanation:

HC ≡ CH > CH₃ – C ≡ CH > CH₂ = CH₂

Acidic strength order.

Discussion

98422.	Sufficient ductility is observed in which of the following type of atomic bond?(a) metallic bond(b) covalent bond(c) ionic bond(d) van der Walls bond
Answer» (a) metallic bond

Discussion

98423.	What is the crystal system of Gypsum (a) Cubic(b) Triclinic(c) Orthorhombic(d) Rhombohedral
Answer» (c) Orthorhombic

Discussion

98424.	Calculate the wavelength for the emission transition if it starts from the orbit having radius `1.3225 nm` ends at `211.6 p m`. Name the series to which this transition belongs and the region of the spectrum.
Answer» Radius of nth orbit of H-like particles `=(0.529n^(2))/Z Å=(52.9n^(2))/Z p m` `r_(1)=1.3225 nm=1322.5 p m =52.9 n_(1)^(2)` `r_(2)=211.6 p m=(52.9n_(2)^(2))/Z` `:. r_(1)/r_(2)=1322.5/211.6=n_(1)^(2)/n_(2)^(2)` or `n_(1)^(2)/n_(2)^(2)=6.25` or `n_(1)/n_(2)=2.5` `:.` If `n_(2)=2, n_(1)=5`. Thus the transition is from `5th` orbit to `2nd` orbit. It belongs to Balmer series. `bar(v)=1.097xx10^(7)m^(-1)(1/2^(2)-1/5^(2))` `=1.097xx21/100xx10^(7) m^(-1)` or `lambda=1/bar(v)=100/(1.097xx21xx10^(7))m` `=434xx10^(-9)m=434 nm` It lies in the visible region.

Discussion

98425.	Which of following statements are correctA. Average velocity of molecules of a gas in a container is zeroB. All molecules in a gas are moving with the same speedC. If an open container is heated from 300 K to 400 K the fraction of air which goes out with respect to originally present is `1/4`D. If compressibility factor of a gas at STP is less than unity then its molar volume is less than 22.4 L at STP
Answer» Correct Answer - A,C,D (C )`n_1T_1=n_2T_2` `nxx300=n_2xx400` `n_2=3/4n` excape out=`(n-3/4n)/n=1/4` (D)`(PV)/(RT)lt1` `Zlt1` Molar volume is less than 22.4 lit. at STP.

Discussion

98426.	Consider the following statements and arrange in the order of true/false as given in the codes. `S_1`:Speed possessed by maximum number of molecules of gas is called most probable speed `S_2`:Molecular speeds are function of temperature for a particular gas. `S_3`:If amount of gas is increased then most probable speed also increases. `S_4`:The root mean square speed of an ideal gas is proportional to `1/sqrtd`A. TTTFB. FFTFC. TTFTD. TFTF
Answer» Correct Answer - C 1.See maximum wells distribution of speed curve. 2.C=f(T) 3.Depends only on temperature 4.`C_(rms)=sqrt((3p)/d)`

Discussion

98427.	Emission transitions in the Paschen series end at orbit n=3 and start from orbit n and can be represented as v=`3.29xx10^(15)(Hz)[1//3^(2)-1//n^(2)]`. Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.
Answer» `v=c/lambda=(3.0xx10^(8) ms^(-1))/(1285xx10^(-9) m)` `=3.29xx10^(15)(1/3^(2)-1/n^(2))` or `1/n^(2)=1/9-(3.0xx10^(8))/(1285xx10^(-9))xx1/(3.29xx10^(15))` `=0.111-0.071=0.04=1/25` or `n^(2)=25` or `n=5` The radiation corresponding to `1285 nm` lies in the infrared region.

Discussion

98428.	A certain gas effuses out of two different vessels A and B.A has a circular orifice while B has a square orifice of length equal to the radius of the orifice of vessel A. The ratio of rate of diffusion of the gas from vessel A to that from vessel B isA. `pi:1`B. `1:pi`C. `1:1`D. `3:2`
Answer» Correct Answer - A Under different conditions of pressure and temperature: rate `alpha(PA)/sqrt(T M) " ":. R_1/r_2 =P_1/P_2 A_1/A_2sqrt((T_2M_2)/(T_1M_1))`

Discussion

98429.	Atomic number `(Z)` of elements is `108`. Write its electronic configuration and name the group to which does it belong?
Answer» `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)4p^(6)4d^(10)4f^(14)` `5s^(2)5p^(6)5d^(10)5f^(14)6s^(2)6p^(6)6d^(6)7s^(2)`. It belongs to group `8` of periodic table.

Discussion

98430.	What is the purpose of using alum in dyeing of cloth?
Answer» Correct Answer - As mordant.

Discussion

98431.	The process by which the amount of a drug in the body decreases after administration but before entering the :systemic circulation is calledA) ExcretionB) First pass effectC) First order eliminationD)Metabolism
Answer» First order elimination

Discussion

98432.	When Rahul took out his shirt from cupboard hung on iron hanger ,it had a stain on it. Identify this stain -a. Oilb. Curryc. Rustd. Grease
Answer» Answer is: c. Rust

98432.

When Rahul took out his shirt from cupboard hung on iron hanger ,it had a stain on it. Identify this stain -a. Oilb. Curryc. Rustd. Grease

Answer»

Answer is:

c. Rust

Discussion

98433.	Double entry system equation
Answer» Double-entry bookkeeping is an accounting system where every transaction is recorded in two accounts: a debit to one account and a credit to another.

Discussion

98434.	let vector A=2i+3j-k which is anti parallel with vector B which has magnitude 6. find vector B
Answer» Let B = b₁ i + b₂ j + b₃ k. Since A and B are anti-parallel, the angle between them is 180°. Then the dot product of A and B is A • B = \|\|A\|\| \|\|B\|\| cos(180°) ⇒ A • B = - \|\|A\|\| \|\|B\|\| The magnitude of A is \|\|A\|\| = \(\sqrt{(2^2+3^2+(-1)^2)}\) = √14 so that A • B = 2b₁ + 3b₂ - b₃ = -6√14 Because A and B are anti-parallel, their cross product is the zero vector. A x B = (3b₃ + b₂) i - (2b₃ + b₁) j + (2b₂ - 3b₁) k = 0 i + 0 j + 0 k ⇒ 3b₃ + b₂ = 0, 2b₃ + b₁ = 0 and 2b₂ - 3b₁ = 0 Now, 2b₂ - 3b₁ = 0 ⇒ b₂ = 3/2 b₁ 2b₃ + b₁ = 0 ⇒ b₃ = -1/2 b₁ so that 2b₁ + 3/2 b₁ - (-1/2 b₁) = -6√14 7b₁ = -6√14 b₁ = -6/7 √14 = -6 √(2/7) Similarly, 2b₂ - 3b₁ = 0 ⇒ b₁ = 2/3 b₂ 3b₃ + b₂ = 0 ⇒ b₃ = -1/3 b₂ so that 2 (2/3 b₂) + 3b₂ - (-1/3 b₂) = -6√14 14/3 b₂ = -6√14 b₂ = -18/14 √14 = -9 √(2/7) Finally, 2 (-6 √(2/7)) + 3 (-9 √(2/7)) - b₃ = -6√14 -39 √(2/7) - b₃ = -6√14 b₃ = 6√14 - 39 √(2/7) = 3 √(2/7) and so the vector B is B = -6 √(2/7) i - 9 √(2/7) j + 3 √(2/7) k or equilvalently, B = -3 √(2/7) (2 i + 3 j - k) B = -3 √(2/7) A

98434.

let vector A=2i+3j-k which is anti parallel with vector B which has magnitude 6. find vector B

Answer»

Let B = b₁ i + b₂ j + b₃ k.

Since A and B are anti-parallel, the angle between them is 180°. Then the dot product of A and B is

A • B = ||A|| ||B|| cos(180°)

⇒ A • B = - ||A|| ||B||

The magnitude of A is

||A|| = \(\sqrt{(2^2+3^2+(-1)^2)}\) = √14

so that

A • B = 2b₁ + 3b₂ - b₃ = -6√14

Because A and B are anti-parallel, their cross product is the zero vector.

A x B = (3b₃ + b₂) i - (2b₃ + b₁) j + (2b₂ - 3b₁) k = 0 i + 0 j + 0 k

⇒ 3b₃ + b₂ = 0, 2b₃ + b₁ = 0 and 2b₂ - 3b₁ = 0

Now,

2b₂ - 3b₁ = 0 ⇒ b₂ = 3/2 b₁

2b₃ + b₁ = 0 ⇒ b₃ = -1/2 b₁

so that

2b₁ + 3/2 b₁ - (-1/2 b₁) = -6√14

7b₁ = -6√14

b₁ = -6/7 √14 = -6 √(2/7)

Similarly,

2b₂ - 3b₁ = 0 ⇒ b₁ = 2/3 b₂

3b₃ + b₂ = 0 ⇒ b₃ = -1/3 b₂

so that

2 (2/3 b₂) + 3b₂ - (-1/3 b₂) = -6√14

14/3 b₂ = -6√14

b₂ = -18/14 √14 = -9 √(2/7)

Finally,

2 (-6 √(2/7)) + 3 (-9 √(2/7)) - b₃ = -6√14

-39 √(2/7) - b₃ = -6√14

b₃ = 6√14 - 39 √(2/7) = 3 √(2/7)

and so the vector B is

B = -6 √(2/7) i - 9 √(2/7) j + 3 √(2/7) k

or equilvalently,

B = -3 √(2/7) (2 i + 3 j - k)

B = -3 √(2/7) A

Discussion

98435.	State two characteristics of balanced diet.
Answer» Two characteristics of balanced diet- 1. It contains different types of foods/nutrients to meet the need of an individual 2. It also has a provision for extra nutrients which can be reserved in the body to withstand short periods of low dietary intake

98435.

State two characteristics of balanced diet.

Answer»

Two characteristics of balanced diet-

1. It contains different types of foods/nutrients to meet the need of an individual

2. It also has a provision for extra nutrients which can be reserved in the body to withstand short periods of low dietary intake

Discussion

98436.	How did don gonzalo and dona laura try to conceal their identity from each other
Answer» Once Don Gonzalo and Dona Laura realize that they are the same old young lovers of Maricela who were separated in life by fate, they make up fictitious stories and conceal their identity.

Discussion

98437.	Passive Voice:When Gonzalo entered the park, his usual bench ............. by the priests. He ......... and his servant, Juanito ............ to rout them out.
Answer» When Gonzalo entered the park, his usual bench had been occupied by the priests. He was annoyed and his servant, Juanito was asked to rout them out.

Discussion

98438.	Fill in the blanks by choosing the appropriate expressions given in brackets:Dona Laura and Don Gonzalo fail to realize what dreams .......... However, they try to impress each other. When Laura seems to read without glasses, Gonzalo does not know that she knows every word ................ (come to, by heart, take refuge)
Answer» come to; by heart.

Discussion

98439.	Fill in the blanks by choosing the appropriate expressions given in brackets:Three priests were sitting on Gonzalo’s usual bench in the park and talking. Gonzalo said that they were ...... time. He could not tolerate their sitting on his bench and ...... (resign himself, idling away, take liberty)
Answer» idling away; resigned himself.

Discussion

98440.	Given below are two statements labeled as Assertion (A) and reason (R) Assertion (A): Energy management is a strategy which helps to utilize energy to maximum. Reason(R): It prevents frustration. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A. b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true
Answer» correct option is a. Both A and R are true and R is the correct explanation of A.

Discussion

98441.	Given below are two statements labeled as Assertion (A) and reason (R) Assertion (A): Labour saving devices reduces psychological fatigue. Reason(R): Preparing tomato puree in mixer grinder saves energy. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A. b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true
Answer» correct option is d. A is false but R is true

Discussion

98442.	Fill in the blanks by choosing the appropriate expressions given in bracketsGonzalo and Laura were annoyed with each other in the beginning. Gonzalo told Laura that she could not ............ and comment on his actions. However, the pinch of snuff he offered her tried to .......... between them. (know by heart, take the liberty, Makepeace)
Answer» take the liberty; make peace.

Discussion

98443.	Given below are two statements labeled as Assertion (A) and reason (R) Assertion (A): Proper lighting and ventilation should be provided in the kitchen. Reason(R): It helps to keep kitchen free from dirt and germ. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A. b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true
Answer» correct option is a. Both A and R are true and R is the correct explanation of A.

Discussion

98444.	What is a User-defined function?
Answer» The user-defined functions are declared and defined in the program by the programmer which perform specific activity and give expected result.

Discussion

98445.	What is the first subscript value of the array in C++?
Answer» The first subscript value of the array in C++ is zero (0).

Discussion

98446.	I was annoyed ______ my failure. A) at B) with C) by D) in
Answer» Correct option is A) at

Discussion

98447.	What is meant by term Sale contract in case of Marine Insurance? Briefly explain the three types of sale contract.
Answer» In Marine Insurance, it is the Sales Contract that decides as to who should take the Insurance. There are different types of sales contracts. 1) F.O.B. (Free on Board) 2) C.I.F. (Cost, Insurance and Freight) 3) C & F (Cost and Freight)

98447.

What is meant by term Sale contract in case of Marine Insurance? Briefly explain the three types of sale contract.

Answer»

In Marine Insurance, it is the Sales Contract that decides as to who should take the Insurance. There are different types of sales contracts.

1) F.O.B. (Free on Board)

2) C.I.F. (Cost, Insurance and Freight)

3) C & F (Cost and Freight)

Discussion

98448.	Where selection statements are used?
Answer» The selection statements are used in decision making process where more than one alternative task to be selected for execution.

Discussion

98449.	The Kulu Valley is situated between (a) Ladakh and Pirpanjal (b) Ranjoti and NagTibba (c) Lesser Himalayas and Siwalik (d) Dhauladhar and Pirpanjal
Answer» (a) Ladakh and Pirpanjal

Discussion

98450.	George has been cured ______ his cold. A) with B) of C) from D) against
Answer» Correct option is B) of

Discussion

Explore topic-wise InterviewSolutions in .

What should come in place of the question mark '?' in the following number series?4, 23, 114, ?, 13641. 4552. 6553. 1454. 234

What should come in place of the question mark '?' in the following number series?3, 5, 8, 12, ?, 231. 222. 173. 134. 155. 14

Frenkel defect and Schottky defect

One male of nitrogen gas at `0.8` atm takes 38 seconds on diffuse through a pinhole, whereas one mole of a compound of xenon with fluorine at 1.6 atm takes 57 secondes to diffuse through the same hole. Calculate molecular weight of the compound.

Which among the following is a basic amino acid? (A) Aspargine (B) Arginine (C) Proline (D) Alanine

Chemical Reactions and Equations Notes Class 10 for revision

Chemical Reactions and Equations:

Chemical reaction:

Chemical Equation:

Balancing Chemical Equation:

Law of Conservation of Mass:

Types of Chemical Reactions:

Classification of Chemical Reactions based on Chemical Change:

Classification of chemical reactions based on energy change:

Effects of Oxidation in Daily Life:

The first `(Delta_IH_1)` and second `(Delta_IH_2)` ionisation enthalpies (in kJ `"mol"^(-1)`) and the `(Delta_(eg)H)` electron gain enthalpy (in kJ `"mol"^(-1)`) of a few elements are given below: The least reactive element is :A. PB. QC. RD. T

What is the basis of the radius ratio theory?

What is buffer solution? Give an example and discuss its activities.

Below what temperature, a gas does not obey ideal gas laws?

The correct option with respect to the Pauling electronegativity values of the elements is : (1) Ga &lt; Ge(2) Te &gt; Se(3) Si &lt; Al(4) P &gt; S

The metal used for making X-ray tube window is : (1) Mg (2) Na (3) Ca (4) Be

The pair that has similar atomic radii is : (1) Mo and W (2) Mn and Re (3) Ti and Hf (4) Sc and Ni

What is common ion effect? Give an example.

The upper stratosphere consisting of the ozone layer protects us from the sun's radiation that falls in the wavelength region of : (1) 600 – 750 nm (2) 0.8 – 1.5 nm (3) 400 – 550 nm (4) 200 – 315 nm

The correct order of atomic radii is : (1) Ce &gt; Eu &gt; Ho &gt; N (2) Eu &gt; Ce &gt; Ho &gt; N (3) Ho &gt; N &gt; Eu &gt; Ce (4) N &gt; Ce &gt; Eu &gt; Ho

Identify the two conjugate acid base pairs in the following NH3 + HCl ⇌ NH4+ + Cl–

Sufficient ductility is observed in which of the following type of atomic bond?(a) metallic bond(b) covalent bond(c) ionic bond(d) van der Walls bond

What is the crystal system of Gypsum (a) Cubic(b) Triclinic(c) Orthorhombic(d) Rhombohedral

Calculate the wavelength for the emission transition if it starts from the orbit having radius `1.3225 nm` ends at `211.6 p m`. Name the series to which this transition belongs and the region of the spectrum.

Emission transitions in the Paschen series end at orbit n=3 and start from orbit n and can be represented as v=`3.29xx10^(15)(Hz)[1//3^(2)-1//n^(2)]`. Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.

A certain gas effuses out of two different vessels A and B.A has a circular orifice while B has a square orifice of length equal to the radius of the orifice of vessel A. The ratio of rate of diffusion of the gas from vessel A to that from vessel B isA. `pi:1`B. `1:pi`C. `1:1`D. `3:2`

Atomic number `(Z)` of elements is `108`. Write its electronic configuration and name the group to which does it belong?

What is the purpose of using alum in dyeing of cloth?

The process by which the amount of a drug in the body decreases after administration but before entering the :systemic circulation is calledA) ExcretionB) First pass effectC) First order eliminationD)Metabolism

When Rahul took out his shirt from cupboard hung on iron hanger ,it had a stain on it. Identify this stain -a. Oilb. Curryc. Rustd. Grease

Double entry system equation

let vector A=2i+3j-k which is anti parallel with vector B which has magnitude 6. find vector B

State two characteristics of balanced diet.

How did don gonzalo and dona laura try to conceal their identity from each other

Passive Voice:When Gonzalo entered the park, his usual bench ............. by the priests. He ......... and his servant, Juanito ............ to rout them out.

What is a User-defined function?

What is the first subscript value of the array in C++?

I was annoyed ______ my failure. A) at B) with C) by D) in

What is meant by term Sale contract in case of Marine Insurance? Briefly explain the three types of sale contract.

Where selection statements are used?

The Kulu Valley is situated between (a) Ladakh and Pirpanjal (b) Ranjoti and NagTibba (c) Lesser Himalayas and Siwalik (d) Dhauladhar and Pirpanjal

George has been cured ______ his cold. A) with B) of C) from D) against

The correct option with respect to the Pauling electronegativity values of the elements is : (1) Ga < Ge(2) Te > Se(3) Si < Al(4) P > S

The correct order of atomic radii is : (1) Ce > Eu > Ho > N (2) Eu > Ce > Ho > N (3) Ho > N > Eu > Ce (4) N > Ce > Eu > Ho