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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. |
(b) (i) Account for the acidic nature of HCIO_(4) In terms of Bronsted - Lowry theory, identify its conjugate base. (ii) Is it possible to store copper sulphate in an iron vessel for a long time? Given: E_(Cu^(2+)//Cu)^(@) = 0.34 V and E_(Fe^(2+)//Fe)^(@) = +0.44 V |
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Answer» Solution :(b) (i) `HClO_(4) (ii) Let us consider the stabilities of the conjugate bases `ClO_(4)^(-), ClO_(3)^(-), ClO_(2)^(-)` and `CIO^(-)`formed from these acid `HClO_(4),HClO_(3),HClO_(2)`, HOCl respectively. These ANIONS are stabilized to greater extent, it has lesser attraction for proton and THEREFORE, will BEHAVE as weak base. Consequently the corresponding acid will be STRONGEST because weak conjugate base has strong acid and strong conjugate base has weak acid. `ClO_(4)^(-)` is the conjugate base of the acid `HClO_(4)`. (ii) `E_("cell")^(@) = E_("ox")^(@) + E_("red")^(@) = 0.44 V + 0.34 V = 0.78 V` These `+ve E_("cell")^(@)` values shows that iron will oxidise and copper will get reduced i.e., the vessel will dissolve. Hence it is not possible to store copper sulphate in an iron vessel. |
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| 2. |
b) i) A non ideal solution has DeltaH_("mixing")gt0. What type of deviation does it show from Raoult's law? ii) What is an azeotrope? |
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Answer» SOLUTION :i) It shows positive deviation. ii) Azeotropes : Binary liquid MIXTURES having the same composition in liquid and vapour phase and boil at a constant TEMPERATURE are Azeotropes Ex: `95%` of ethyl ALCOHOL and `5%` water by volume. |
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| 3. |
b) How is a metal-carbon pi bond formed in metal carbonyls? |
| Answer» Solution :`M-C pi` BOND is formed by the donation of a pair of electrons from a FILLED d-orbital of metal into the vacnat antibonding `pi` orbital of carbon monoxide. This is CALLED BACK bonding. | |
| 4. |
B-H-B bridge in B_2H_6 is formed by the sharing of : |
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Answer» 2 electrons |
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| 5. |
How does Hinsberg's reagent react with ethyl amine? Write the equation. |
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Answer» Solution :Benzene SULPHONYL CHLORIDE `[C_(6)H_(5)SO_(2)CL]` is called Hinsberg reagent i) Ethyl amine react with Hinsberg.s reagent to form N-Ethyl benzene sulphonamide [Soluble in ALKALI] 
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| 6. |
b) Give the composition of carnallite. |
| Answer» SOLUTION :The COMPOSITION of carnallite `KCI. MgCl_(2)6H_(2)O` | |
| 7. |
b) Give reason: - i) o-nitrophenol and p-nitrophenol can be separated by steam distillation. ii) There is a large difference in boiling points of alcohols and ethers. |
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Answer» SOLUTION :i) o-nitrophenol is steam volatite but p-nitrophenol is not. II) The large DIFFERENCE in boiling points of alcohols and ethers DUE to the presence of H-bonding in the alcohols |
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| 8. |
(b) Give simple chemical tests to distinguish between the following pairs of compounds : (i) Butanal and Butan-2-one. (iii) Benzoic acid and Phenol. |
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Answer» Solution :(i) BUTANAL and Butan-2-one : `underset("Butanol")(CH_(3)CH_(2)CH_(2)CHO), underset(Butan-2-one)(CH_(3)-overset(O)overset(||)C-CH_(2)-CH_(3))` (1) Butanal on warming with Tollen.s reagent gives silver mirror. This test is not given by butan-2-one (KETONES). (2) Butanal on warming with a mixture containing Fchling A and Fchling B in equal volumes and HEATING gives a reddish brown precipitate. This test is not given by butan-2-one. (ii) Benzoic acid and Phenol : (1) `NaHCO_3` test - To a saturated solution of sodium hydrogen-carbonate, ADD a pinch of the compound. If an effervescence takes place, it is benzoic acid. Phenol does not give this test. (2) Ester test - Heat a little of the compound with ethyl alcohol and a few drops of cone. `H_2SO_4`. A fruity ester smell is given by benzoic acid. Phenol does not give this test. |
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| 9. |
B gives red colouration with FeCl_(3). |
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Answer» ` A " is " CH_(3)-underset(CH_(3))underset(|)(CH)-overset(O)overset(||)(C)-OH` |
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| 10. |
B-F bond order in BF_3 is : |
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Answer» 1 |
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| 11. |
(b) Explain why it is much less activating than the amino group, -NH_(2). |
| Answer» Solution : (B) DUE to involvement of lone PAIR nitrogen with the carbonyl group. | |
| 12. |
Explain the influence of a catalyst on rate of reaction. |
Answer» Solution :A catalyst increases the rate of a reaction by decreasing ENERGY of ACTIVATION `(Ea)`. A catalyst provides a NEW reaction path for the reaction. Because a catalyst forms an catalyst is regenerated. 
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| 13. |
Explain decarboxylation reaction with an example. |
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Answer» Solution :The process of removal of `CO_(2)` from sodium SALT of carboxylic acid using DRY soda lime `[NaOH + CaO]` is CALLED DECARBOXYLATION. Decarboxylation of carboxylic acid gives hydrocarbons. `underset("Sodium carboxylate")(R-COONa)overset((NaOH+CaO))underset("Heat")rarr underset("Hydrocarbon")(R-H)+Na_(2)CO_(3)` |
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| 14. |
Explain Williamson's ether synthesis. |
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Answer» Solution :b) Alkyl halides on heating with alkoxide in alcoholic MEDIUM gives ETHERS, this REACTION is called williamson.s ether syntheis `R-ON a+X-R^(1)overset(Delta)RARR R-O-R^(1)+Nax` `underset("methodie")underset("Sodium")(CH_(3)-ON a+I)+underset("iodide")underset("Methyl")(I-CH_(3))overset(Delta)rarr underset("methane")underset("Methoxy")(CH_(3)-O-CH_(3))` |
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| 15. |
(b) Define thermoplastics and thermosetting polymers with two examples of each. |
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Answer» Solution :THERMOPLASTIC polymers : Those polymers (linear or slightly branched long CHAIN MOLECULES), which are CAPABLE of softening on heating and hardening on cooling are called thermoplastics, These polymers posses intermolecular forces of attraction intermediate between elastomers and fibres. EXAMPLES are polythene, polyvinyl chloride, polystyrene etc. Thermosetting polymers : Those polymers (cross-linked or heavily branched molecules) which on heating do not soften and cannot be remoulded are called thermosetting polymers. On heating they undergo extensive cross-linking in moulds and becomes infusible. Examples are Bakelite, urea-formaldehyde resins etc. |
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| 16. |
(b) Describe a chemical test to distinguish between (i) Ethanal and propanal (ii) Benzldehyde and Acetophenone (iii) Pronepan 2 one and propan 3 one |
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Answer» SOLUTION :(i) See Q 30 (b)(i) SET I (D.B)-2013 (ii) See Q 30or (ii) Set I (O.D)-2011 (iii) See Q 30 (ii) Set -I (O.D)-2013 |
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| 17. |
B-complex is an often prescribed vitamin. What is complex about it and what is its usefulness ? |
| Answer» Solution :It is a group of vitamins which contains vitamins `B_1, B_2,B_6,B_12` , BIOTIN , pantothenic acid( VITAMIN `B_5`), folic acid and nicotinic acid (vitamin `B_3`). Since it is not a single vitamin but is a group of vitamins , that is why , it is called vitamin B-complex. it is required to release energy from food and to promote healthy skin and MUSCLES. Its deficiency causes beriberi (vitamin `B_1`) and PERNICIOUS anaemia (Vitamin`B_12`). | |
| 18. |
Complete the following equations: i) 2HCHO+" conc. KOH"rarr ii) CH_(3)CHO+NH_(2)OHrarr iii) CH_(3)COOH+PCl_(5)rarr |
Answer» Solution :i) TWO molecules of aldehydes which do not contain `alpha -` HYDROGEN atom react with strong alkali and undergo REDOX reaction with strong alkali and undergo redox reaction to produce a primary alcohol and a salt of carboxylic acid. This rection is called as cannizaro.s reaction.  ii) ACETALDEHYDE reacts with hydroxylamine to gice acetaldoxime  iii) Carboxylic acids reacts with phosphorus pentachloride to form corresponding acid chlorides `underset("(acetic acid)")(CH_(3)-COOH+PCl_(5))rarr underset("(acetyl chloride)")(CH_(3)-COCl+POCl_(3)+HCl)` |
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| 19. |
b) Complete the following equation: i) C_(2)H_(5)OH+SOCl_(2)rarr ii) |
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Answer» SOLUTION :b) i) `C_(2)H_(5)OH+SOCl_(2)rarr C_(2)H_(5)Cl+SO_(2)+HCL` ii) 
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| 20. |
(b) Calculate the volume strength of 3.58 N H_(2)O_(2) solution . |
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Answer» SOLUTION :The strength of `H_(2)O_(2) " is " 3.58` equivalentsper litres …(Eqn .4ii) (1 eq of oxygenoccupies `5.6` = 20 litres ) Thus1 litre of `H_(2)O_(2)` at NTP gives a volume of 20 litres . That is to say - strength of `H_(2)O_(2)` is 20 V . |
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| 21. |
b) Calculate the pH of a buffer solution consisting of 0.04 M CH_3 COOH and 0.4M CH_3 COONa. What is the change in the pH after adding 0.01 mol of HCI to 500 ml of the above buffer solution. Assume that the addition of HCI causes neglible change in the volume . Given (K_(s)=1.8xx10^(-5)). |
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Answer» Solution :(b)pH of BUFFER `[H_3 O^+]=` ANTILOG of `(-pH)` `underset(0.4-alpha)(CH_3 COOH_((aq))) hArr underset(0.4)( CH_3 COOH_((aq))^(-))+underset(alpha)(H_((aq))^(+)1)` `underset(0.4)(CH_3 COOH_((aq))) to underset(0.4)( CH_3 COOH_((aq))^(-))+underset(0.4)(Na_((aq))^(+))` `[H^+]=(K_(a)[CH_3 COOH])/([CH_3 COO^-])` `[CH_3 COOH]=0.4 - alpha cong 0.4` `[CH_3 COO]=0.4+alpha cong 0.4` `THEREFORE [H^(+)] = (K_(a)(0.4))/((0.4))` `[H^+]=1.8xx10^(-5)` `therefore pH=-log (1.8xx10^(-5)) =4.74` Addition of 0.01 mol HCI to 500 ml of buffer Added `[H^+]=(0.01 mol)/(500 mL )=(0.01 mol)/((1)/(2)L)` `=0.02M` `CH_3 COOH_((aq)) hArr CH_3 COO_((aq))^(-)+H_((aq))^(+)` `underset(0.4-alpha)(CH_3 COOH_((aq))) hArr underset(0.4)( CH_3 COOH_((aq))^(-))+underset(alpha)(H_((aq))^(+)1)` `underset(0.4)(CH_3 COOH_((aq))) to underset(0.4)( CH_3 COOH_((aq))^(-))+underset(0.4)(Na_((aq))^(+))` ` underset((0.02))(CH_3 COO^(-))+underset(0.02)(HCI) to underset(0.02)(CH_3 cOOH)+underset(0.02)(CI^-)` `[CH_3 COOH]=0.4-alpha +0.02` `=0.42 - alpha cong 0.42` `[CH_3 COO^-] =0.4+alpha -0.02` `=0.38+alpha cong 0.38` `[H^+]=((1.8xx10^(-5))(0.48))/((0.38))` `[H^+]=1.9xx10^(-5)` `=5-log1.99` `=5-0.30` `=4.70` |
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| 22. |
b) Calculate Delta_(r)G^(@) for the following reaction: Fe_((aq))^(+2)+Ag_((aq))^(+)rarr Fe_((aq))^(+3)+Ag(s).""("Given : "E_("cell")^(@)=+0.03V, F=96500C). |
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Answer» Solution :B) `Delta_(F)G^(@)=-nFE^(@)` `Delta_(r)G^(@)=-1xx96500xx0.03` `Delta_(f)G^(@)=2899J` |
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| 23. |
b) Calculate the concentration of hydrogen ion in moles per litre of a solution whose pH is 5.4 |
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Answer» Solution :(b) PH of the solution `=5.4` `[H_3 O^+]=` ANTILOG of `(-pH)` = antilog of `(-5.4)` = antilog of `(-6+0.6)=BAR(6).6` `=3.981xx10^(-6)` i.e, `3.98xx10^(-6) xx10^(-6)"MOL dm"^-3` |
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| 24. |
b) Between methyl amine and ammonia which has lower pK_(b) value and why? |
| Answer» SOLUTION :Mehylamine is stronger BASE so it has LOWER `PK_(B)` value | |
| 25. |
b) An element crystallizes in a foc lattice. The edge length of the unit cell is 400 pm. Calculate the density of the unit cell. ("molar mass"="60 g mol"^(-1)) ("Avogadro number"=6.02 xx 10^(23)) |
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Answer» SOLUTION :`d=(zM)/(a^(3)N_(A))` `"Given, In FCC"` `Z=4, M="60 g MOL"^(-1), a="400 pm "=400xx10^(-10)cm^(3)` `d=("4 atomz "xx"60 g mole"^(-1))/((400xx10^(-10)cm)^(3)xx(6.023xx10^(23)" atoms mol"^(-1)))` `=6.226g cm^(-3)` |
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| 26. |
(b) A solution of glycerol (C_(3)H_(8)O_(3)) in water was prepared by dissolving some glycerol in 500 g of water. This solution has a boiling point of 100.42^(@)C. What mass of glycerol was dissolved to make this solution? (K_(b) for water = 0.512 K g "mol"^(-1)) |
| Answer» SOLUTION :(B) `w_(2)=37.7g` | |
| 27. |
(a)Zr and Hf have almost identical radii : Give reason.(b)Name the gas liberated when Lanthanoids (Ln) react wtih acids. |
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Answer» Solution :(a)Poor shielding of 4f ELECTRONS decreases the size of Hf due to lanthanoid contraction. Henceit maintain the size equiavlent to Zr. (b)With water lanthanoids gives HYDROXIDES with the liberation of hydrogen. `6Ln + 6H_(2)O to 2 Ln(OH)_(3) + 3H_(2)` With DIL ACID they liberate hydrogen `Ln + dil acid toH_(2)` gas. |
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| 28. |
Azoxybenzene can be obtained by treatment of nitrobenzene with |
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Answer» `O_(2)` |
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| 29. |
Azoxybenzene can be obtained by the treatment of mitro-benzene with : |
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Answer» `O_2` |
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| 30. |
Azotrops are |
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Answer» LIQUID MIXTURE which distill unchanged in composition |
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| 31. |
Azotropic mixture are |
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Answer» those BOIL at different temperature |
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| 32. |
Azomethane, (CH_3)_2N_2decomposes with a first-order rate according to the equation (CH_3)_2N_2(g)toN_2(g) + C_2 H_6(g)In the beginning the initial pressure was 36.2 mm and after 15 min. the total pressure was 42.4 mm. Calculate the rate constant. |
| Answer» SOLUTION :`1.25 xx 10^(-2) "MIN"^(-1)` | |
| 33. |
Azoetropes are constant boiling mixtures, which like a pure chemical compound boils at a constant temperature and distills over completely at same temperature without change in composition. There may be two type of binary solution which gives azeotropic mixture. Type-I: Mixture showing minimum in "Boiling point-Composition curve". Type-II: Mixture which showns a maximum in "Boiling point-Composition curve" Both types are shown below: Let the solution of "water-ethanol" corresponds to Type-I and at point 'C", it had a composition of 95.6% of by weight in vapour phase". if this solution is boiled at 78.13^(@)C then find out the % by wt.of water in "liquid phase" (Given T_(C)(temperature at point C) = 78.13^(@)C:- |
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Answer» `95.6%` |
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| 34. |
Azoetropes are constant boiling mixtures, which like a pure chemical compound boils at a constant temperature and distills over completely at same temperature without change in composition. There may be two type of binary solution which gives azeotropic mixture. Type-I: Mixture showing minimum in "Boiling point-Composition curve". Type-II: Mixture which showns a maximum in "Boiling point-Composition curve" Both types are shown below: Which of the type above (i.e., Type or Type-II) shows negative deviation from Raoul's law? |
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Answer» SOLUTION of Tupe-I |
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| 35. |
Azoetropes are constant boiling mixtures, which like a pure chemical compound boils at a constant temperature and distills over completely at same temperature without change in composition. There may be two type of binary solution which gives azeotropic mixture. Type-I: Mixture showing minimum in "Boiling point-Composition curve". Type-II: Mixture which showns a maximum in "Boiling point-Composition curve" Both types are shown below: For figure (I) and (II) predict which of the component(i.e., A and B) is more volatile? |
| Answer» Answer :B | |
| 36. |
Azobenzene can be obtained by reducing nitrobenzene with |
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Answer» `Sn+HCL` 
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| 37. |
Azodye test is used for the identification of |
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Answer» ALIPHATIC - `1^(0)` - amine |
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| 38. |
Azo dyes are prepared from ………………… . |
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Answer» Aniline + PHENOL |
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| 39. |
Azo dye test is given by |
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Answer» All amines |
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| 40. |
Azo dye test is used to distinguish between : |
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Answer» aldehydes and ketones |
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| 41. |
Azo couplingreactionreaction isnot possiblewithh |
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Answer» `C_(6)H_(5)OH` |
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| 42. |
Azo dye is prepared by the coupling of phenol and |
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Answer» DIAZONIUM chloride |
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| 43. |
Azeotropic mixture ofHCl and H_(2) has |
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Answer» `48HCl` |
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| 44. |
Azeotropic mixture of water (B.P. = 100°C) and nitric acid (B P = 83°C) boils at 393 5 K During fractional distillation of mixture, it is possible to obtain |
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Answer» NEITHER `HNO_3` nor `H_2O` |
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| 45. |
Azeotropic mixture of HCl and water has: |
| Answer» Answer :D | |
| 46. |
Azeotropes are |
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Answer» liquid MIXTURES which distil UNCHANGED in composition |
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| 47. |
Azeotrope mixture cannot be separate by ............. |
| Answer» SOLUTION :FRACTIONAL DISTILLATION | |
| 48. |
Azeotrope mixture are: |
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Answer» MIXTURE of two solids |
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| 49. |
Axial distances are a = bne c and axial angles are a = 90^(0) = beta, Y = 120^(@) in the system |
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Answer» `NaWO_(2)` |
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| 50. |
(a)Write general reaction and derive the units of rate constant.(b)Based on that write the rate constant for zero,first and 2^(nd) order reaction. |
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Answer» Solution :(a)General REACTION:aA+bB`to` cC+dD The differential rate expression of general reacion is as under: Rate=`-(d[R])/(dt)=K[A]^(x)[B]^(y)`……(i) `therefore k=(Rate)/([A]^(x)[B]^(y))`…….(II) Where ,order of reaction (x+Y)=n and n=0,1,2,3,`(1)/(2),(3)/(2)`....ETC The Si units of CONCENTRATION is mol `L^(-1)` and time `(s^(-1))` which is unit of concentration /time.Order of reaction =n,so unit of n is (mol `L^(-1))^(n)` Put these value in equation (ii) and the unit of K `k=("concentration")/("time")xx(1)/("concentration")` `=(mol L^(-1))/(time)xx(1)/((mol L^(-1))^(n))` Unit of k=`((mol L^(-1))^((1-n)))/("second")` Unit of k=`(mol L^(-1))^(1-n)S^(-1)` Where ,n=order of the reaction . Note :For time ,in place of second,minutes ,hours,day years etc.may present. 
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