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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Even though electrons are attract by the +ve nucleus, yet they dont fall in it. Explain. |
| Answer» this is due to the stability of the atom. U ACTUALLY are telling a drawback of rutherford's atomic model. u should remember one thing that electron always revolves in orbits meaning it always has particular energy level. the consequences u are stating will take place only when the electron is losing energy with its every turn. due to the loss of energy it will get closer & to nucleus & will end up falling into it so, the nucleus will become unstable & will get destructed. neil bohr removed this drawback by PROPOSING his theory which stated that electrons revolve in particular orbits of different energy levels. further, these revolve only in those orbits whose angular momentum is the integral multiple of the factor h/2pie. he also stated that electrons don't lose energy by the expiry of time he called this condition as ground STATE. also, if protons & electrons collide they won't make a SINGLE neutral body but would get unstable & will be destroyed instead. u should remember that the entire things which i stated is due to the stability of the atomic structure because i understand that its very difficult for u to understand the entire thing but just remember the stability factor & u will get the entire thing. so, u should remeber that the electron doesn't lose its energy due to its revolution in various energy orbitals | |
| 2. |
explain me in detail about dalton's law of partial pressure for making a project....with easy examples |
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Answer» According to Dalton‟s atomic theory, all matter, whether an ELEMENT, a compound or a mixture is composed of small particles called atoms. The postulates of this theory may be stated as follows: (i) All matter is made of very tiny particles called atoms. (ii) Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction. (iii) Atoms of a given element are identical in mass and chemical properties. (iv) Atoms of different elements have different MASSES and chemical properties. (v) Atoms combine in the ratio of small whole numbers to form compounds. (vi) The relative number and kinds of atoms are constant in a given compound. Drawbacks of Dalton’s Atomic Theory: The atom is further subdivided into protons, neutrons and electrons. The atoms of same elements are not similar in all respect. They may vary in mass and density. These are known as isotopes. For example: chlorine has two isotopes having mass numbers 35 a.m.u and 37 a.m.u. Atoms of different elements are not different in all respects. Atoms of different elements that have the same atomic mass are called isobar. According to Dalton atoms of different elements combine in simple whole number ratio to form compounds. This is not seen in complex organic compounds like sugar C12H22O11. The theory fails to explain the existence of allotropes like Diamond and Graphite which having different properties even these are made up of same kind ot atom NAMELY Carbon. The introduction of matter wave concept by de Broglie, the principle of UNCERTAINTY by Heisenberg etc., paved the way for modern atomic theory [Modification in Dalton‟s atomic theory] Modifications in Dalton’s atomic theory - Modern atomic theory are as follows. Atom is considered to be a divisible particle . Atoms of the same element may not be similar in all respects. eg: Isotopes (17Cl35,17Cl37 ) Atoms of different elements may be similar in some respects eg. Isobars (18Ar 40 , 20Ca 40 ) Atom is the smallest particle which takes part in chemical reactions. The ratio of atoms in a molecule may be fixed and integral but may not be simple e.g., C12H22O11 is not a simple ratio (Sucrose) Atoms of one element can be changed into atoms of other element by transmutation. The mass of an atom can be converted into energy. This is in accordance with Einstein‟s equation E = mc2 |
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| 3. |
A metal which displaces copper from copper(II)sulphate apart from zinc |
| Answer» MAGNESIUM is the ANSWER | |
| 4. |
How much oxygen i will get from 2.5 cm3 hydrogen peroxide decomposition?? |
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Answer» Decomposition of Hydrogen PEROXIDE: |
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| 5. |
What is the chemistry |
| Answer» the BRANCH of science concerned with the substances of which MATTER is COMPOSED, the investigation of their PROPERTIES and reactions, and the use of such reactions to form new substances. | |
| 7. |
What are thermodynamic process |
| Answer» A thermodynamic process is the energetic development of a thermodynamic SYSTEM PROCEEDING from an INITIAL state to a final state. PATHS through the SPACE of thermodynamicvariables are often specified by holding certainthermodynamic variables constant. | |
| 8. |
My 5th std sister has science fair project plz help me to choose topic. |
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Answer» There are MANY things that can be made like-MODELS of Volcano,SOLAR System,Phases of Moon,ALSO Models showing pollution in world or URBANISATION. |
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| 9. |
Why does Brass get discoloured in air ? |
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Answer» BRASS GET DISCOLOURED IN AIR BECAUSE AIR CONTAIN DIFFERENT-DIFFERENT TYPES OF GASES BUT DUE TO REACTION WITH HYDROGEN SULPHIDE WITH BRASS LOOKS DISCOLOURED IN AIR. |
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| 10. |
Balance the equation..if u have to add any substance pls add it..!!Al + NaOH ---------> NaAlO2 + H2 |
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Answer» 2Al+2NaOH+2 |
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| 11. |
A) Calculate the molecular masses of the following compounds :i) Acetic acid (CH3COOH) ii) Ethanol (C2H5OH) iii) Carbon dioxide b) Calculate the mass of the following : i) 0.5 mole of N2 gas(mass from mole of molecule) ii) 0.5 mole of N atoms ( mass from mole of atom) iii) 3.011 × 1023 number of N atoms(mass from number) iv) 6.022 × 1023 number of N2 molecules (mass from number ) c) Calculate the number of particles in each of the following : i) 46 g of Na atoms (number from mass) ii) 8 g of O2 molecules ( number of molecules from mass) iii) 0. 1 mole of carbon atoms ( number from given moles) |
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Answer» These are very simple questions provided you know the formulae. |
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| 12. |
Say some chemical reactions. Neither too simple nor too tough. |
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Answer» OK, |
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| 14. |
What is the name of the substance with formula Cu(H2O)6SO4? |
| Answer» COPPER(II) SULPHATE HEXAHYDRATE is the ANSWER. | |
| 15. |
Differentiate between molecules of elements and molecules of compounds |
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Answer» MOLECULES of elements contain the ATOMS of only one KIND i.e only of 1 substance/element. whereas molecules of compounds contain the atoms of different kind i.e. of different elements |
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| 16. |
Please tell me fast the que is in attachment |
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Answer» In ACIDIC medium, the nucleophile (in this CASE, the CH3O- group) is added to the more substituted CARBON of epoxide and a hydrogen atom attaches to the oxygen of the epoxide group to form an OH group ATTACHED to the less substituted carbon of the epoxide (reverse in case of basic medium) . |
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| 17. |
Please give me all the stoichiometric formulas |
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Answer» All stoichiometric formulas are RELATED to the mole concept. |
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| 18. |
What mass of phosphoric acid is produced when 6.2 grams of phosphorus reacts with nitric acid? |
| Answer» ANS: 26.133gP + 5 nitric acid====== phosphoric acid + 5 NO2+ wateri.e. 1 EQUIVALENT of phosphorous GIVES 1 equivalent of phasphoric acid.Equivalent weight of P = 7.75Equivalent weight of phosphoric acid= 98/3 | |
| 19. |
I want definition of collaids |
| Answer» COLLOIDS are unstable heterogeneous SOLUTIONS that SHOW TYNDALL effect .......... | |
| 20. |
Calculate the no of moles present in : a)18g of mg (mg=24)b)12.044 x 10^22 no of neon atom |
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Answer» A) No. of MOLES = GIVEN MASS/ molar mass |
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| 21. |
Hydrogen exists in three isotopic forms. why are the isotopes of hydrogen chemically a like |
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Answer» Because they have only ONE PROTON which REPRESENTS HYDROGEN |
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| 22. |
Why sodium carbonate is used in the manufacture of soap in cold process |
| Answer» Sodium carbonate soaps HELP REMOVE INSOLUBLE oils from materials, such as motor oils, human sweat stains and vegetable GREASE. | |
| 23. |
Why sodium carbonate is added in cold process of soap manufacturing? Explain the reason for using? |
| Answer» | |
| 24. |
What are the hydroxides,oxides,halides of s-block elements? |
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Answer» The s-block elements of the Periodic Table are those inwhich the last electron enters the outermost s-orbital. Asthe s-orbital can accommodate only TWO ELECTRONS, twogroups (1 & 2) belong to the s-block of the Periodic Table.Group 1 of the Periodic Table consists of the elements:lithium, sodium, potassium, rubidium, caesium andfrancium. They are collectively known as the alkali metals.These are so called because they form hydroxides |
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| 25. |
What is joule thomson effect? |
| Answer» the change of TEMPERATURE of a gas when it is allowed to expand without doing any EXTERNAL WORK. The gas becomes COOLER if it was initially below a certain temperature or HOTTER if initially above it... | |
| 26. |
Hard water isa) a clear solutionb) potablec) semi solid suspensiond) colloid solutionchoose one option n provide reason |
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Answer» It is a colloid it is neither a CLEAR LIQUID nor a SUSPENSION they RANGE up to 2.0 to 1,0000nm SOLUTION. |
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| 27. |
The physical property of a hydrocarbon is determined by the chain . is it true or false ???? |
| Answer» YES the PHYSICAL PROPERTY of hydrocarbon is determined by CHAIN | |
| 28. |
1.)How will u test for an Alcohol.????2.) A mixture of ethyene and oxygen is burnt for welding. Can u tell why a mix. of ethyne and air is not used.????3.) Which element has a total of two shells,with three electrons in its second shell as in its first shell.???? |
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Answer» 1. R-OH+Na---------> R-O-Na + H₂ |
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| 29. |
To precipitate soap from the saponification mixture, sodium chloride is added asA) dilute solutionB) concentrated solutionC) solid powderD)all of these |
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Answer» All of these are USED |
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| 30. |
From the formulae listed below, choose one, corresponding to the salt having the given description:AgCl, CuCO3, CuSO4.5H20, KNO3, NaCl, NaHSO4, Pb(NO3)2, ZnCO3, ZnSO4.7H20.'On heating the salt, changes from green to black.' |
| Answer» COPPER carbonate (CuCO₃) SALT on heating CHANGES from green to BLACK. | |
| 31. |
bromine water react with unsaturated compounds to form colourless then why it does not reacts with saturated |
| Answer» it is because SATURATED COMPOUNDS CONTAINS SINGLE BONDS only...... | |
| 32. |
Mehod of learning periodic table |
| Answer» FIRST buy or MAKE a periodic table CHART and paste it on a wall which you see DAILY and then try to read atleast a GROUP in that table such that you can remember easily | |
| 33. |
What kind of uses of ISOBARS are there? |
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Answer» They can be USED to find areas of low or high pressure over a broad area (like the U.S.), and they can tell us how intense the system may be. On weather MAPS, you may have NOTICED areas that have a large “L” or “H” over a REGION with lines circling around them. The “L” stands for low pressure. |
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| 34. |
Can anyone give me the latin names of first 20 elements?? advance Thanks |
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Answer» Hydrogen 1. Atomic Number- 1 SYMBOL- H Orgin of Name- Greek 'hydro' and 'genes' means water forming Helium 1. Atomic Number- 2 2. Symbol- He 3. Orgin of Name- Greek 'Helios" meaning sun Lithium 1. Atomic Number- 3 2. Symbol- Li 3. Orgin of Name- Greek 'Lithos' meaning stone Berylium 1 . Atomic Number- 4 2. Symbol- Be 3. Orgin of Name- Greek name for beryl, 'beryllo' Boron 1. Atomic Number-5 2. Symbol- B 3. Orgin of Name- the ARABIC 'buraq', which was the name for BORAX Carbon 1. Atomic Number- 6 2. Symbol- C 3. Orgin of Name- Latin 'carbo' meaning charcoal Nitrogen 1. Atomic Number- 7 2. Symbol-N 3. Orgin of Name- Greek 'nitron' and 'genes' meaning nitre forming Oxygen 1. Atomic Number- 8 2. Symbol- O 3. Orgin of Name- Greek 'oxy' and 'genes' meaning acid forming Fluorine 1. Atomic Number- 9 2. Symbol- F 3. Orgin of Name- Latin 'fluere' meaning to flow Neon 1. Atomic Number- 10 2. Symbol- Ne 3. Orgin of Name- Greek 'neos' meaning new Sodium 1. Atomic Number-11 2. Symbol- Na 3. Orgin of Name- the english word soda (Natrium in Latin) Magnesium 1. Atomic Number-12 2. Symbol- Mg 3. Orgin of Name- Magnesia, a district of Eastern Theassally in Greece Aluminium 1. Atomic Number- 13 2. Symbol- Al 3. Orgin of Name- Latin name for 'alumen' meaning bitter salt |
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| 35. |
In electrolysis of water, why is the volume of gas collected over one electrode double the volume of gas collected over the other electrode? |
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Answer» Balance reaction for electrolysis of water is: |
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| 36. |
what would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? |
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Answer» It WOULD be lilke this |
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| 37. |
Difference between: nucleus and nucleons,valence shell and penultimate shell? |
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Answer» A nucleus is at the center of an atom, and it is that collection of particles, protons and neutrons, that make up the nucleus of that atom. Because ATOMIC nuclei are composed of protons and neutrons, we have come up with the term nucleon to describe any particle that makes up an atomic nucleus. That MEANS EITHER a proton or a neutron, when we talk about them as part of the nucleus of an atom, can be properly called a nucleon. The nucleus of an atom is said to be MADE up of NUCLEONS. |
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| 38. |
1. Give reasons: i) Mgcl2 is soluble in water but insoluble in acetone,while methene is insoluble but soluble in acetone. ii) Iron displaces copper from a solution of a copper salt. the reaction is de |
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Answer» Mgcl2 is SOLUBLE in water because it is highly ionisible and s dissolving agent while acetone is a chemical REAGENT by which instead on dissolving it GIVES a explosive sound or changes COLOUR. |
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| 39. |
How does the tendency to gain electrons change as we go down the 16thgroup of periodic table? Why? |
| Answer» Actually it never changes as in 16 the group all the elements have 4 VALENCY ELECTRONS in OUTERMOST shell so they can neither accept nor LOSE the electrons. | |
| 40. |
Difference Between Collide,Suspension And True Solution |
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Answer» Collidal Solution is SOMEWHAT HAZY and light if made to fall in this solution gets scattered |
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| 41. |
Different types of clothes in different seasons |
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Answer» We wear COTTON CLOTHES in summer because they ALLOW the air to pass through it, in winter we wear woolen clothes because they defend the BODY from getting cold |
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| 42. |
Why are unsaturated hydrocarbons are more reactive thhan saturated hydrocarbons ? |
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Answer» UNSATURATED hydrocarbons are more REACTIVE than saturated hydrocarbons because unsaturated hydrocarbon contain HIGH ENERGY pie bond which are very unstable and high electron DENSITY so they are very reactive. |
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| 43. |
Can you explain me why tearing of paper is a physical change and burning of paper a chemical change? |
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Answer» In tearing of paper the paper TORN can be put it back in place by STICKING the pieces together but in chemical change the BURNT paper can not be got back |
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| 44. |
Some questions regarding Nomenclature of Organic CompoundsI'm in 10th class. So please answer accordingly.Q1)If a functional group & Alkyl group are present, who will get the lowest number?Q2)If 2 functional groups are present, then who will get the lowest number?Q3)In ethyl & methyl group who will get the lowest number?Q4)CH3-COO-C2H5 has 2 names-ethyl ethanoate & methyl propanoate. Why?Q5)Is =O to be included in a chain?Q6)If multiple bond & alkyl group are present; which one will get the lowest number? |
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Answer»
2 ans ; it depends upon on which POSITION the functional group is present 6ans; multiple bond 5ans; YES it depends upon the functional group attach . but which CHAIN you are TALKING about |
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| 45. |
What is the differece between sedimentation and decantation |
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Answer» Sedimentation is the SETTLING down of rocks at the bottom |
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| 47. |
Lightning of matchstick near petroleum |
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Answer» If a matchstick is lit near PETROLEUM the place where U have kept the PETROL it may catch FIRE and the whole place may burn so it may be dangerous |
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| 48. |
If 20 ml of solution of NaOH is found to be completely neutralized with 10ml of H2SO4,calculate the volume of same H2SO4 needed to neutralize 10 ml of NaOH. What will be the colour of phenolphthalein |
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Answer» 5 ml it doesn't SHOWS COLR in PHENOLPHTHALEIN |
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| 49. |
Acidic & basic radicals. |
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Answer» Acid RADICAL is the anion or NEGATIVE ion in the salt which has come from the "PARENT" acid eg. SO4^2- sulphate from sulphuric acid H2SO4 Cl^- chloride from hydrochloric acid HCl Basic radical is the cation or positive ion from the "parent" base/alkali (most often a METAL ion) eg. Na^+ SODIUM, Cu^2+ copper, Al^3+ aluminium NH4^+ ammonium.. |
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