94420 + Interview Questions in Chemistry in Class 12

1.	Degree if dissociation is nearly equal to 1 for
Answer» STRONG ACIDS and strong bases Strong acids and WEAK bases Weak acids and strong bases Weak acids and weak bases Answer :A

Discussion

2.	Degradation of one mole of glucose provides :
Answer» 36 MOLE of ATP 10 mole of ATP 315 mole of ATP 3 mole of ATP Answer :A

Discussion

3.	Defined molecularity of a reaction.
Answer» SOLUTION :Molecularity of a reaction is the total number of REACTANT SPICES that are INVOLVED in elementary step.

Discussion

4.	Defined rate law and constant.
Answer» Solution :(i) Rate LAW. The EXPRESSION in which reaction rate is given in terms of molar concentration of the reactants with each term raised to some power , Which mayor may not be same as the stoichiometric coefficient of the reaction species in a balanced chemical equation. `xA+yBrarr` products Rate `=k[A]^m[B]^n` k = Rate constant (ii) Rate constant : for a reaction involving the reactants A and B. Reaction rate = `=k[A]^m[B]^n` the constant k is CALLED rate constant of the reaction. If `[A] = 1M and [B] = 1M,`Reaction rate = k Thus, the rate constant (k) of a reaction is equal to the rate of reaction when the concentration of each reactant is equal to 1 mol `L^(-1)` . The change in the concentration of reactant product per unit TIME under the condition of unit nation of all the reactant.

Discussion

5.	Defined rate of the reactiongive the unit of rate
Answer» Solution :(i) In a chemical REACTION, the change in the construction of the spices involved in a chemical reaction PER unit time gives the rate of reaction. `A rarrB` Rate `=-(Delta[A])/(dt)"(or)"(Delta[B])/(dt)` (ii) Unit of rate `=("unit of CONCENTRATION")/("unit of time")` `"mol L"^(-1) s^(-1)`

Discussion

6.	Define zeolites with an example. Define peptisation.
Answer» Solution :Zeolite is the nature given to some alumino silicates of METALS with formula `M_(x//n) [ Al_2O_3)_x(SiO_2)_3].m H_2O` Peptisation is the process of converting a precipitate into a COLLOIDAL sol by the addition of a suitable electrolyte to it. For example, a colloidal solution of ferric hydroxide is FORMED by adding a small amount of `FeCl_3`to the precipitate. The precipitate adsorbs `Fe^(3+)`IONS from the electrolyte on its surface to form colloidal sol. `Fe(OH)_3 + Fe^(3+) to [Fe(OH_3)]Fe^(3+)`

Discussion

7.	Define zero order reaction . Given the unit for its content (k).
Answer» f f Solution :Zero ORDER Reaction . The reaction in which the RATE of reaction is independent of the concentration of the reactions is called zero order reaction. Rate `=k[A]^0` =k where k is rate CONSTANT , Its unit is MOLE `L^(-1)s^(-1)`

Discussion

8.	Define with equation (a ) Riemer - Tiemann Reaction( b) Williamson's Symthesis
Answer» Solution :See Q. 15 ( i) Paper - 2010 ,Delhi Board ,SET-II [page 78] ( B) See Q.15 (ii) paper - 2010 ,Delhi Board .set -I [page 188].

Discussion

9.	Define zero order reaction. Give the unit for its rate constant (k).
Answer» Solution :Zero Order REACTION. The reaction in which the rate of reaction is INDEPENDENT of the concentration of the reactants is called zero order reaction. Rate `=K [A]^(0)` =k Where k is the rate CONSTANT. Its UNIT is `mol L^(-1) s^(-1)`

Discussion

10.	Define void.
Answer» Solution :The EMPTY spaces present between the atoms or the IONS when they are packed WITHIN the crystal are CALLED VOIDS.

Discussion

11.	Define van't Hoff factor . How is it related to the degree of dissociation ?
Answer» Solution :The van't Hoff factor is defined as the ratio of observed colligative property produced by a given CONCENTRATION of electrolyte to a property observed for the same concentration of non- electrolyte solution . Van't Hoff factor is related to the DEGREE of dissociation of the FORMULA : ` ALPHA = (i - 1)/(n'-1)`

Discussion

12.	Define Van't Hoff's factor.
Answer» Solution :i= `("Normal molar MASS")/("ABNORMAL molar mass") ` OR = `("Oberved colligatve property")/("CALCULATE COLLIGATIVE property")`OR Total no. of moles of particles I = `("after association/dissociation")/("NUMBER of moles of particles")` before association/dissociation

Discussion

13.	Define van’t Hoff factor.
Answer» Solution :Van’t HOFF FACTOR : It is the ratio of the normal MOLAR mass to the observedmolar mass of the solute.

Discussion

14.	Define unit cell.
Answer» Solution :It is the smallest repeating UNIT of a CRYSTAL which when placed in 3 dimensions gives the crystal lattice. OR Unit cell is the smallest portion of a crystal lattice which, when repeated in different DIRECTIONS, generates the entire lattice.

Discussion

15.	Define Tyndall effect
Answer» SOLUTION :TYNDALL EFFECT: The SCATTERING of light by the colloidal particles in a colloidal solution is called tyndall effect.

Discussion

16.	Define transition temperature in solubility of a solid in a liquid.
Answer» SOLUTION :the TEMPERATURE at which the trend of SOLUBILITY changes (e.g., first INCREASES and then decreases) is CALLED the transition temperature.

Discussion

17.	Define transition elements. Give their general outer electronic configuration.
Answer» Solution :The ELEMENTS which have partly filled d-sub outershells in their elementary form or in their commonly occurring oxidation states. General outer ELECTRONIC configuration : `(n-1)d^(1) - 10 ns^(1) - 2`

Discussion

18.	Define tranquillizers and give one example.
Answer» SOLUTION :Drugs which REDUCE anxiety and PRODUCE feeling of wellbeing are called tranquillizers. For EXAMPLE, EQUANIL or seconal.

Discussion

19.	Define threshold energy.
Answer» Solution :It is the MINIMUM energy of the molecules ,for EFFECTIVE collisions to form PRODUCTS

Discussion

20.	Define thermoplastics and give two examples of thermoplastics.
Answer» Solution :Thermoplastics are linear POLYMERS which are hard at room temperature. Such polymers are hard at room temperature and on heating they become soft or fluid like and then can be moulded in any SHAPE. They show reversible changes when heated and cooled. Thus, they can be used again and again. Two COMMON EXAMPLES of thermoplastics are polythene and POLYSTYRENE.

Discussion

21.	Define thermoplastics and thermosetting polymers with two examples of each.
Answer» Solution :Thermoplastics are linear polymers which are hard at room TEMPERATURE. Such polymers are hard at room temperature and on heating they become soft or FLUID like and then can be moulded in any SHAPE. They show reversible CHANGES when heated and cooled. Thus, they can be used again and again. Two common examples of thermoplastics are polythene and polystyrene.

Discussion

22.	Define thermoplastics.
Answer» Solution :POLYMERS which can be repeatedly SOFTENED on heating and hardened on cooling and can be used again and again without any change in their chemical composition and mechanical strength are called thermoplastics. For example, polythene , teflon, polystrene, nylon , PVC, PAN , etc.

Discussion

23.	Define thermoplastic and thermosetting polymers. Give one example of each.
Answer» Solution : Thermoplastics : Polymers in which the intermolecular forces of attraction are in between those of elastomers and fibres are CALLED thermoplastics. E.g., Nylon-6, PVC, etc. Thermosetting polymers : These are semi-fluid substances with low molecular masses which when heated in a mould undergo a PERMANENT change in chemical COMPOSITION to give HARD, infusible and INSOLUBLE mass. E.g., Bakelite.

Discussion

24.	Define thermodynamic equilibrium. Mention differenttypes of thermodynamic equilibria.
Answer» SOLUTION :Therinodynamic EQUILIBRIUM: .A system is said to have attained a state of thennodynamic equilibrium if there is no change inany thermodynamic functions or state functions LIKE ENERGY, pressure,volume, etc. with TIME. For a system to be in thermodynamic equilibrium, it has to attainfollowing three types of equilibrium: (1) Thermal equilibrium (2) Chemical equilbrium (3) Mechanical equilibrium.

Discussion

25.	Define the thermoplastic and thermosetting polymers. Give one example of each.
Answer» Solution :Thermoplastics : Thermoplastics are the ones in which intermolecular forces of attraction are intermediate of these of elastomers and fibres. Process of heat SOFTENING, moulding and cooling can be repeated many times as desired without AFFECTING mechanical properties of POLYMER. e.g., Polythene, Polypropylene, PVC. Thermosetting polymers : Thermosettingpolymers are the ones which on heating change irreversibily into hard, rigid and infusible materials are called thermosetting polymers. Since three dimensional molecule structure is rigid and does not soften on heating e.g., Phenol-formaldehyde (bakelite) RESINS, melamine formaldehyde resins.

Discussion

26.	Define the terms osmosis and osmotic pressutt. Is the osmotic pressure of a solution a colligative property ? Explain.
Answer» SOLUTION :OSMOTIC pressu.re is a colligative property as it depends on the number of moles of SOLUTE particles and not on other entities.

Discussion

27.	Define the terms, 'osmosis' and 'osmotic pressure'. What is the advantage of using osmotic pressure as compared to other colligative properties for the determination of molar masses of solutes in solutions ?
Answer» Solution :The process of flow of solvent from a solution through a semi-permeable membrane is calledosmosis. The extra pressure that MUST be APPLIED on the solution to STOP the flow of solvent through the semi-permeable membrane is called osmotic pressure. The osmotic pressure METHOD has the advantage over other methods as pressure measurementis around the room temperature and the molarity of the solution is used in place of molality.

Discussion

28.	Define the terms monomer and polymer.
Answer» SOLUTION :Monomer: The repeating structural UNITS of polymer which are derived from simple and reactive molecules linked to one another by covalent bonds are called MONOMERS. Polymer: A large molecular weight complex compound which is FORMED by the repeated combination of simple units (monomers) is called polymer.

Discussion

29.	Define the terms :Mole fraction
Answer» Solution :Mole FRACTION : The mole fraction of a component in a mixture is defined as the ratio of the number of moles of the component to the total number of moles of all the components in the mixture. i.e., Mole fraction of a complex `= ("Number of moles of the component")/("Total number of moles of all components")` Mole fraction is DENOTED by .x.. If in a binary solution, the number of moles of the SOLUTE and the solvent are `n_(A)` and `n_(B)` respectively, then the mole fraction of the solute in the solution is given by, `chi_(A)=(n_(A))/(n_(A)+n_(B))`, Similarly, the mole fraction of the solvent in the solution is given as : `chi_(B)=(n_(B))/(n_(A)+n_(B))`.

Discussion

30.	Define the terms :Molarity
Answer» SOLUTION :Molarity : Molarity (M) is DEFINED as the number of moles of the solute DISSOLVED in one Litre of the solution. It is expressed as : MOLALITY (M) `= ("Moles of solute")/("Volume of SOLVENT in Litre")`

Discussion

31.	Define the terms :Molality
Answer» SOLUTION :Molality : Molality (m) is defined as the number of MOLES of the solute per kilogram of the solvent. It is expresed as: Molality (m) `= ("Moles of solute")/("MASS of solvent in kg")`

Discussion

32.	Define the terms :Mass percentage.
Answer» Solution :Mass percentage : The mass percentage of a component of a solution is DEFINED as the mass of the solute in grams PRESENT in 100 g of the solution. It is expressed as : Mass % of component `= ("Mass of component in solution")/("TOTAL mass of solution")xx 100`

Discussion

33.	Define the terms : (i) Elastomers (ii) Flibres (iii) Thermoplastics
Answer» SOLUTION :For ANSWER, CONSULT SECTION 2

Discussion

34.	Define the terms: (i) Biomolecules (ii) Carbohydrates (iii) Reducing Sugars.
Answer» Solution :(i) BIOMOLECULES : These are the ORGANIC compounds which form the basis of life, e.g. proteins, carbohydrates ETC. (ii) Carbohydrates: These are the optically active polyhydroxy aldehydes or ketones or the substances which give such substances on hydrolysis e.g. glucose, fructose etc. (iii) Reducing Sugars : All the monosaccharides and disaccharides EXCEPT SUCROSE which reduce Fehling.s solution or Tollen.s reagent are called reducing sugars.

Discussion

35.	Define the terms: (i) Activation Energy (ii) Molecularity . (iii) Rate Constant.
Answer» Solution :(1) Activation Energy : It is the excess energy which must be supplied to the REACTING species in ADDITION to energy already possesed by them so that their energy becomes equal to the THRESHOLD energy. (i) Molecularity : It is the total number of reacting species which must COLLIDE together to bring about a simple reaction. (ii) Rate Constant : It is equal to the rate of the reaction when molar CONCENTRATION of cach reactant is unity

Discussion

36.	Define the terms given below : (a) Conductivity (b) Molar conductivity What are their units ?
Answer» Solution :(a) Conductivity (K) : Conductivity of a material in `S m^(-1)` is its conductance when it is 1 m long and its AREA of cross-section is `1 m^(2)`? The conductivity has the SI units as `SM^(-1)`? but quite often k is expressed in S `cm^(-1)`?. `1 S cm^(-1) = 100 S m^(-1)` (b) Molar conductivity (`Lambda_(m)`): Molar conductivity of a solution at a given concentration is the conductance of the volume V of the solution containing one mole of electrolyte kept between two electrodes with area of cross-section A and distance of unit LENGTH. `Lambda_(m) = (KA)/l` Since, l =1 and A =V, we have `Lambda_(m) = kV` The units of molar conductance are `S cm^(2) MOL^(-1)`.

Discussion

37.	Define the terms adsorbent and adsorbate.
Answer» Solution :ADSORBENT is the solid SUBSTANCE on the SURFACE of which adsorption OCCURS and ADSORBATE is the substance which gets adsorbed on the solid surface.

Discussion

38.	Define the term "Tyndall effect".
Answer» Solution :When a strong beam of LIGHT is passed through a colloidal solution, the path of the light BECOMES VISIBLE when viewed from a DIRECTION at right angle to that of the incident light. This is due to the FACT that sol particles absorb light energy and then scatter it in all directions. The phenomenon of scattering of light by the sol particles is called Tyndall effect.

Discussion

39.	Define the term therapeutic index.
Answer» Solution :(i) Therapeutic index is DEFINED as the ratio between the maximum tolerated dose of a drug (above which it becomes toxic) and the minimum curative dose (below which the drug is INEFFECTIVE) (II) HIGHER the value of therapeutic index, safer is the drug.

Discussion

40.	Define the term Tyndall effect.
Answer» SOLUTION :When a beam of light is passed through colloidal solution, its PATH becomes CLEARLY visible. It is called Tyndall effect. It happens because of SCATTERING of light by colloidal PARTICLES.

Discussion

41.	Define the term transition element.
Answer» SOLUTION :TRANSITION element is defined as the one which has INCOMPLETELY filled d-orbitals in its ground state or in any one of its OXIDATION STATES.

Discussion

42.	Define the term tempering and nitriding.
Answer» Solution :Tempering : In this process the hardened and steek is heated to a temperature much below REDNESS and then it is slowly COOLED. The product obtained in NEITHER so hard nor so brittle. ` ` Nitriding : In this process steel is heated in the atmosphere of AMMONIA. The surface of steel is COATED with a hard iron nitride.

Discussion

43.	Define the term solution. How many types of solutions are formed ? Write briefly about eachtype with an example.
Answer» Solution : A HOMOGENEOUS mixture of TWO or more non-reacting substances whose composition varieswithin certain fixed limits is known as solution. Types of solutions : 1. When both solute and solvent are in solid state e.g., alloys. 2. When the solute is in solid and solvent is a liquid, e.g., sugar or salt in water. 3. When solute is in solid state and solvent is in gaseous state e.g., iodine vapours in AIR. 4 When both solute and solvent are in liquid state 2.g., alcohol in water. 5. When solute is in liquid state but solvent is in solid state e.g., zinc amalgam. 6. When solute is in liquid but solvent is in gaseous state e.g., water vapours in air. 7. When both solute and solvent are in gaseous state e.g., air. 8. When solute is in gaseous but solvent is in liquid state e.g., AERATED drinks.9. When solute is in gaseous state and solvent is in solid state e.g., dissolved gases in MINERAL.

Discussion

44.	Define the term 'polymerisation'
Answer» Solution :POLYMERIZATION is the overall process of the formation of a high molecular mass macromolecule from one or more monomers by LINKING TOGETHER a large number of repeating structural units through COVALENT bonds.

Discussion

45.	Define the term polymerization.
Answer» SOLUTION :Polymerization is a process of FORMATION of a high molecular mass polymer from one or more monomers by linking together of REPEATING STRUCTURAL UNITS with covalant bonds.

Discussion

46.	Define the term polymerisation.
Answer» Solution :The PROCESS of formation of a high molecular mass macromolecule from one or more monomers by linking together a large number of repeating STRUCTURAL UNITS through covalent bonds is CALLED polymerisation.

Discussion

47.	Define the term polymerisation .
Answer» Solution :Polymerisation is process of FORMATION of HIGH molecular mass polymer from two or more monomers by LINKING together of REPEATING structural units by covalent bonds.

Discussion

48.	Define the term peptization and mention its cause.
Answer» Solution :It is the process of converting a PPTS into a colloidal SOL by shaking it with small amount of electrolyte with dispersion medium . Ppts adsorb ONE of the ions of the electrlyte on its surface .

Discussion

49.	Define the term osmotic pressure.
Answer» Solution : The EXTERNAL pressure that must be applied to the solution side to STOP the passage of solvent intothe solvent through the SEMIPERMEABLE MEMBRANE is CALLED the osmotic pressure.

Discussion

50.	Define the term order of reaction for chemical reactions.
Answer» Solution :Sum of the POWERS of CONCENTRATION of the reactants in the rate law EXPRESSION is called the order of that chemical reaction.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Degree if dissociation is nearly equal to 1 for

Degradation of one mole of glucose provides :

Defined molecularity of a reaction.

Defined rate law and constant.

Defined rate of the reactiongive the unit of rate

Define zeolites with an example. Define peptisation.

Define zero order reaction . Given the unit for its content (k).

Define with equation (a ) Riemer - Tiemann Reaction( b) Williamson's Symthesis

Define zero order reaction. Give the unit for its rate constant (k).

Define void.

Define van't Hoff factor . How is it related to the degree of dissociation ?

Define Van't Hoff's factor.

Define van’t Hoff factor.

Define unit cell.

Define Tyndall effect

Define transition temperature in solubility of a solid in a liquid.

Define transition elements. Give their general outer electronic configuration.

Define tranquillizers and give one example.

Define threshold energy.

Define thermoplastics and give two examples of thermoplastics.

Define thermoplastics and thermosetting polymers with two examples of each.

Define thermoplastics.

Define thermoplastic and thermosetting polymers. Give one example of each.

Define thermodynamic equilibrium. Mention differenttypes of thermodynamic equilibria.

Define the thermoplastic and thermosetting polymers. Give one example of each.

Define the terms osmosis and osmotic pressutt. Is the osmotic pressure of a solution a colligative property ? Explain.

Define the terms, 'osmosis' and 'osmotic pressure'. What is the advantage of using osmotic pressure as compared to other colligative properties for the determination of molar masses of solutes in solutions ?

Define the terms monomer and polymer.

Define the terms :Mole fraction

Define the terms :Molarity

Define the terms :Molality

Define the terms :Mass percentage.

Define the terms : (i) Elastomers (ii) Flibres (iii) Thermoplastics

Define the terms: (i) Biomolecules (ii) Carbohydrates (iii) Reducing Sugars.

Define the terms: (i) Activation Energy (ii) Molecularity . (iii) Rate Constant.

Define the terms given below : (a) Conductivity (b) Molar conductivity What are their units ?

Define the terms adsorbent and adsorbate.

Define the term "Tyndall effect".

Define the term therapeutic index.

Define the term Tyndall effect.

Define the term transition element.

Define the term tempering and nitriding.

Define the term solution. How many types of solutions are formed ? Write briefly about eachtype with an example.

Define the term 'polymerisation'

Define the term polymerization.

Define the term polymerisation.

Define the term polymerisation .

Define the term peptization and mention its cause.

Define the term osmotic pressure.

Define the term order of reaction for chemical reactions.