Explore topic-wise InterviewSolutions in Current Affairs.

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.	How is 'cast iron' different from 'pig iron' ?
Answer» Solution :IRON OBTAINED from blast furnace that contains 4% carbon is CALLED pig iron. Pig iron when melted with scrap iron gives iron with 3% carbon called cast iron. It is extremely HARD and brittle.

2.	How is cast iron different form pig iron?
Answer» <P> Solution :Pig iron : This from of iron is obtained from BLAST furnace. It contains approximately 4% CARBON and other impurities (S, P, Si, Mn, etc) in small amounts. Cast iron : This form of iron is formed by melting pig iron with scrap iron and coke using hot air blast. It has slightly lesser carbon content (3% approximately). It is extremely hard and brittle.

3.	Howiscast iron differentfor pig iron ?
Answer» Solution :Theiron obtainedfromblastfunaceis CALLED PIG iron. It contains about4% carbon and MANY otherimpurities (e.g., S, P, Si, Mn) insmalleramounts. Castiron,on theother hand, is made bymeltingpig iron with scrapironand cokeusinghot airblast.It has slightly LOWER carbon content (about 3%) and isextramelyhard and brittle.

4.	How is Brownian movement responsible for the stability of sols ?
Answer» SOLUTION :STIRRING effect DUE to Brownian MOVEMENT does not ALLOW the particles to settle down

5.	How is Buna-N prepared ? Give it s use .
Answer» Solution :(i) Buna -N is PREPARED by the POLYMERISATION of acrylonitrile and buta- 1, 3- diene ` underset("Buta-1,3-diene")(n CH_2=CH-CH=CH_2) + underset("Vinyl CYANIDE ")(nCH_2=underset(CN)underset(\|)(C)H) to underset("Buna-N")((--CH_2-CH=CH-CH_2-underset(CN)underset(\|)(C)H-CH_2 --)_n)` (ii) It isused in themanufactureof hosesand tank linings .

6.	How is carbon black obtained ?
Answer» By HEATING wood at high temperature in ABSENCE of air By heating coal at high temperature in absence of air By burning hydrocarbons in a limited supply of air by heating coal at high temperature in presence of air Solution :Carbon black is obtained by bunning hydrocarbons in a limited supply of air. Carbon black particles are usually spherical in SHAPE and LESS regularly crystalline than GRAPHITE.

7.	How is Brownian movement responsible for stability of sols ?
Answer» Solution :Brownian MOVEMENT KEEPS the particles in motion and does not allow them to SETTLE down.

8.	How is boron trifluoride obtained from boron trioxide ?
Answer» Solution :(i) BORON trifuloride is obtained by the TREATMENT of calcium fluoride with boron trioxide in presence of conc. Sulphuric acid. `B_(2)O_(3)+3CaF_(2)+3H_(2)SO_(4)OVERSET(Delta)to 2BH_(3)+3CaSO_(4)+3H_(2)O` (ii) It can also be obtained by treating boron trioxide with carbon and fluorine. `B_(2)O_(3)+3C+3F_(2)to 2BF_(3)+3CO` (iii) In the laboratory pure `BF_(3)` is prepared by the thermal decomposition of benzene DIAZONIUM tetrafluoro borate. `PhN_(2)BF_(4)overset(Delta)to BF_(3)+PhF+N_(2)`

9.	How is bond order related to stability of molecules ?
Answer» Solution :Higher the bond order GREATER the STABILITY.

10.	How is benzoic acid prepared from: (1) n-butyl benzene (2) toluene?
Answer» SOLUTION :When an alkyl BENZENE is heated with strong oxidizing asgents likeacidic or alkline `KMnO_(4)` or acidified `K_(2)Cr_(2)O_(7)`, etc. gives aromatic carboxyllic acid. The alkyl SIDE chain gets oxidised to `-COOH` group irrespective of the size of the chain.

11.	How is Benzonitrile converted to Benzophenone?
Answer» SOLUTION :Benzonitrile REACTS with phenyl magnesium bromide in presence of dry ether to give an imine complex which on acid hydrolysis GIVES a benzophenone. During reaction benzonitrile and phenyl magnesium bromide should be TAKEN in equimolecular proportion.

12.	How is benzoic acid prepared from benzene?
Answer» Solution :Benzene is CONVERTED to BENZOIC acid in the FOLLOWING SEQUENCE of steps.

13.	How is benzoic acid obtained from phenyl ethene?
Answer» Solution :When phenyl ethene is heated with strong OXIDISING AGENTS like acidic `KMnO_(4)` or acidic `K_(2)Cr_(2)O_(7)`, BENZOIC acid is obtained.

14.	How chlorobenzene can be converted into benzoic acid.
Answer» SOLUTION :m-bromobenzoic ACID :

15.	How is benzoic acid converted to aniline and benzylamine?
Answer» Solution :BENZOIC acid on heating with ammonia gives benzamide which PRODUCES aniline with BROMINE and alkali. `C_(6)H_(5)COOH + NH_(3) overset(Delta)rarr C_(6)H_(5)CONH_(2) underset(NaOH)overset(Br_(2))rarr C_(6)H_(5)NH_(2)` Benzyl amine is formed when benzamide is reduced. `C_(6)H_(5)CONH_(2) overset(LiAlH_(4))rarr C_(6)H_(5)CH_(2)NH_(2)`

16.	How is bezamide obtained from benzoic acid ?
Answer» SOLUTION :When benzoic ACID reacts with ammonia, to form ammonium benzoate which on heating undergoes dehydration forming benzamide.

17.	How is benzaldehyde converted into Cinnamic acid? Give the equation.
Answer» SOLUTION :In this REACTION aromatic ALDEHYDE is HEATED with an ACID anhydride and its corresponding sodium salt.

18.	How is bakelite prepared?
Answer» Solution :O-hydroxy methyl phenol reacts with phenol toform a COMPOUND with two RINGS joined by `-CH_(2)-` linkage. This PROCES continues further to form cross linked three dimensional space network solid at two ORTHO and one-para positions. THUS, the network of solid is called bakelite. It is used in making switches, handles of cooker,frying pans, etc.

19.	How is bakelite made and what is its major use ? Why is it called thermo-setting polymer?
Answer» Solution :BAKELITE is prepared by CONDENSATION REACTION of phenol and formaldehyde. It is used in making ELECTRICAL switches and switch boards.

20.	How is bakelite made and what is its major use ? Why is bakelite a thermosetting polymer ?
Answer»

21.	How is aspirin prepared ?
Answer» Solution :Aspirin is prepared by acetylation of SALICYLIC acid using a MIXTURE of acetic ANHYDRIDE and glacial acetic acid.

22.	How is anisole prepared from benzene diazonium chloride?
Answer» Solution :The `N_2Nl` GROUP can be REPLACED by alkoxy group by warming with alcohol or by acyloxy group by BOILING with carboxylic acids.

23.	How is aniline prepared on large scale ? How will you convert it into : (i) Benzonitrile (ii) Acetanilide ?
Answer» SOLUTION :

24.	How is Aniline prepared from nitro benzene?
Answer» SOLUTION :Nitro benzene is reduced to ANILINE by passing hydrogen GAS in the presence of finelydevided NICKEL, palladium or platinum OR by heating with Sn and CONC. HCl or Fe and Conc. HCl.

25.	How is aniline prepared from chlorobenzene?
Answer» Solution :When aniline is treated with nitrous acid, BENZENE diazonium CHLORIDE (diazonium salt) is FORMED. The diazonium salt when treated with CUPROUS chloride gives CHLOROBENZENE.

26.	How is aniline obtained from benzoic acid ?
Answer» SOLUTION :

27.	How is aniline obained from benzoic acid?
Answer» SOLUTION :

28.	How is aniline converted to Benzene diazonium chloride ? Give equation.
Answer» Solution :Benzene diazonium chloride is prepared by the reaction of aniline with NITROUS acid at 273 - 278 k. `C_(6)H_(5)NH_(2)+HNO_(2)+HCl overset(273-278k)rarrC_(6)H_(5)N_(2)Cl+2H_(2)O`

29.	How is aniline converted to benzyl alcohol?
Answer» Solution :Aniline is converted to benzene diazonium CHLORIDE, which in turn is converted to benzonitrile. Hydrolysis of benzonitrile gives benzoic acid, which on reduction gives benzyl alcohol. `C_(6)H_(5)NH_(2)overset(NaNO_(2))underset(HCl)rarr C_(6)H_(5)N=NCl overset(KCN)underset(CUCN)rarr C_(6)H_(5)CN` `overset(H_(3)O^(-))rarrC_(6)H_(5)COOH overset(LiAlH_(4))rarr C_(6)H_(5)CH_(2)OH`

30.	How is aniline converted to benzene? Discuss the reactions
Answer» SOLUTION :VIA DIAZONIUM SALT

31.	How is Aniline converted into Phenol?
Answer» Solution :Aniline is diazotized with NITROUS ACID `(NaNO_2 + HCl)` at 273- 278K to give benzene diazonium CHLORIDE which on further treatment with HOT water in the presence of mineral acid gives phenol

32.	How is an ester obtained from carboxylic acid?
Answer» Solution :When a carboxylic acid is heated with an alcohol in the presence of concentrated sulphuric acid or dry hydrogen chloride gas, an ESTER is obtained. The reaction is called Fischer esterification. This is REVERSIBLE reaction and the formation of ester is favoured using EXCESS of alcohol in the presence of conc. `H_(2)SO_(4)`. Here, concentrated sulphuric acid ACTS as dehydrating agent. `underset("carboxylic acid alchol")(R - overset(O)overset(\|\|)C- OH + HO-R) overset(H^(+))hArr underset("ester")(R-overset(O)overset(\|\|)(C)-O-R+H_(2)O+)` e.g., `underset("acetic acid")(CH_(3)) - overset(O)overset(\|\|)(C) - OH + H underset("ethyl alchol")-O C_(2)H_(5) underset(Delta)overset(conc. H_(2)SO_(4))to underset("ethyl acetate")(CH_(3)-overset(O)overset(\|\|)(C) -OC_(2)H_(5) +H_(2)O)` `underset("propionic acid")(CH_(3)-CH_(2))-overset(O)overset(\|\|)(C) - OH+ CH_(3) - OH underset(Delta)overset(conc.H_(2)SO_(4))to underset("methyl propiobate")(CH_(3)-CH_(2))- overset(O)overset(\|\|)(C) - OCH_(3) + H_(2)O`

33.	How is aniline converted in phenyl isocyanide ? Write the equation.
Answer» Solution :Aniline on HEATING with CHLOROFORM and ALCOHOLIC KOH form PHENYL isocyanide.

34.	How is ammonia manufactured on the large scale by Haber's process?
Answer» Solution :(1) Ammonia is manufactured on a large scale by Haber's PROCESS. (2) In this process, N, and H, gases are allowed to react at high pressure of `200 x 10_(5)` Pa (200 atm) and temperature of 700 K. (3) The best catalyst used is highly porous finely divided iron with small amount of promoters like Moor `K_(2)O` and `Al_(2)O_(3)`whichhelp to ATTAIN chemicalequilibrium fast. `N_(2(g)) + 3H_(2(g)) underset(200 "atm")overset( 700K)to 2NH_(3(g))""Delta_(f)H =- 46.1 kJ mol^(-1)` (4) Since in the reaction, there is a decrease in number of moles, according to Le Chatelier's principle, increase in pressure will give more ammonia. (5)Asshown in the flow chart `N_(2)`and `H_(2)` in theproportionof 1:3are fed in thecompressorand passedovercatalystwhichgives `NH_(3)`unreaccted `N_(2),H_(2)`alongwith `NH_(3)`is furthercompressed to formliquefied`NH_(3)`which is collectedat THEBASE.

35.	How is ammonia prepared?
Answer» Solution :(i) Ammonia is formed by the hydrolysis of UREA. `NH_(4)CONH_(2)+H_(2)Orarr 2NH_(3)+CO_(2)` (II) Amoonia is prepared in the laboratory by heating an ammonium salt with a base. `2NH_(4)^(+)+OH^(-)rarr 2NH_(3)+H_(2)O` `2NH_(4)Cl+CaOrarr CaCl_(2)+2NH_(3)+H_(2)O` (III) It can also be prepared by heating a metal nitrides such as magnesium nitride with water. `Mg_(3)N_(2)+6H_(2)rarr 3MG(OH)_(2)+2NH_(3)`

36.	How is ammonia manufactured industrially?
Answer» Solution : Ammonia is prepared on industrial scale by Haber.s process. `N_2(g) + 3H_2(g) iff 2NH_3(g) , DeltaH^(@) = - 46.1 kJ " mol"^(-1)` There are 2 molecules in the product side and 4 molecules in the reactant side. Thus, there is a decrease of pressure as the products are formed. Also, heat is EVOLVED when the REACTANTS change into products. According to Le Chatelier.s principle, high pressure and low temperature would favour the formation of ammonia. It has been FOUND that the optimum conditions of pressure and temperature are `200 xx 10^(5)` PA (about 200 atmospheres) and around 700 K, respectively. Iron oxide with SMALL amounts of `K_2O and Al_2O_3` act as cataysts. The flow chart for the production of ammonia by Haber.s proces is given below:

37.	How is ammonia manufactured?
Answer» Solution :(1) Ammonia is manufactured on a large scale by HABER's process. (2) In this process, N, and H, gases are ALLOWED to react at high pressure of `200 x 10_(5)` Pa (200 atm) and temperature of 700 K. (3) The best catalyst used is highly porous finely divided iron with small amount of promoters like Moor `K_(2)O` and `Al_(2)O_(3)`whichhelp to attain chemicalequilibrium fast. `N_(2(g)) + 3H_(2(g)) underset(200 "atm")overset( 700K)to 2NH_(3(g))""Delta_(f)H =- 46.1 kJ MOL^(-1)` (4) Since in the reaction, there is a decrease in number of moles, according to Le Chatelier's principle, increase in pressure will GIVE more ammonia. (5)Asshown in the flow chart `N_(2)`and `H_(2)` in theproportionof 1:3are fed in thecompressorand passedovercatalystwhichgives `NH_(3)`unreaccted `N_(2),H_(2)`alongwith `NH_(3)`is furthercompressed to formliquefied`NH_(3)`which is collectedat thebase.

38.	How is aminoethane obtained from ethanal (acetaldehyde)?
Answer» SOLUTION : `underset("Ethanal(ACETALDEHYDE)")(CH_3-oversetunderset(\|\|)(O)(C )-H) overset(LiAlH_4)(to) underset("ethanal")(CH_3CH_2OH) + NH_3 overset(Al_2O_3)(to) underset("ETHANAMINE")(CH_3CH_2NH_2) + H_2O`

39.	How is aminoethane obtained from ethanal ?
Answer» Solution :`underset("Ethanal ")(CH_3 CHO +NH_3 ) underset(-H_2 O) overset("HEAT")toCH_3 - overset(H )overset(\| ) C = NHoverset(H_2 //Ni ) tounderset("AMINOETHANE ")(CH_3 CH_2 NH_2)`

40.	How is aminoethane (ethylamine) obtained from ethanal (acetaldehdye)?
Answer» Solution :`underset("Ethanal")(CH_(3)CHO) +NH_(3) underset(("Reductive amination"))OVERSET(H_(2)//NI" or "NaBH_(3)CN)to[CH_(3)CH=NH]tounderset("Ethylamine")(CH_(3)CH_(2)NH_(2))`.

41.	How is amino group can be directly converted into nitro group? Explain with an example.
Answer» Solution :Amino group can be directly converted into niro group using car.s ACID `(H_(2)SO_(5))` (or) persulphuric acid `(H_(2)S_(2)O_(8))` (or) peroxytrifluoro ACETIC acid `(F_(30C.COOOH)` as oxidising AGENT.

42.	How is alkylation of amines carried ? Give example.
Answer» Solution :Alkylmon of Aliphatic Amine : All the three types ex amines react with alkyl HALIDE to fonn quaternary ammonium SALT as the final product in presence of excess alkyl halide. `C_(2)H_(5)-Br+C_(2)H_(5)overset(..)NH_(2)overset(-HBr)(rarr)(C_(2)H_(5))_(2)overset(..)NH overset(C_(2)H_(5)Br)(rarr)(C_(2)H_(5))_(4)N^(+)Br^(-)` Alkylation of AROMATIC Amine : Aromatic amine are also alkylated by alkyl halide

43.	How is aliphatic primary amine distinguished from aromatic primary amine?
Answer» Solution :When treated with `HNO_(2)(NaNO_(2)+HCl)` at `0^(@)C`, aliphatic primary amines give ALCOHOLS. `CH_(3)CH_(2)NH_(2)overset(HNO_(2))rarr CH_(3)CH_(2)-overset(o+)N-=overset(Theta)NCloverset(Delta)underset(H_(2)O)rarrCH_(3)CH_(2)OH+N_(2)` AROMATIC primary ainines give a stable DIAZONIUM salt.

44.	How is adsorption of a gas related to its critical temperature ?
Answer» Solution :Higher is the cirtical temperture of a GAS, greater is the ease of LIQUEFACTION, i.e., greater are the van der Walls forces of attraction and hence greater is the adsorption.

45.	How is adsorption of a gas related to its critical temperature?
Answer» SOLUTION :HIGHER is the critical TEMPERATURE of a GAS, greater are the van der WAALS forces of attraction and hence greater the adsorption.

46.	How is adsorption applied in the decolourisation of sugar?
Answer» Solution :Sugar prepared from molasses is decolourised to REMOVE COLOURED impurities. Animcal charcoal is applied to adsorb COLOURING impurities and sugar is purified.

47.	How is adipic acid obtained from cyclohexene?
Answer» SOLUTION :When CYCLOHEXENE is HEATED with acidified `KMnO_(4)`, adipic acid(Hexane-1,6-dioic acid) is obtained.

48.	How is activation energy of a reaction affected i) by using a catalyst ii) by increasing the temperature?
Answer» Solution :i) By using a catalyst, the ACTIVATION ENERGY is DECREASED. ii) By increasing the TEMPERATURE, the activation energy is decreased.

49.	How is acidity cured with cimetidine or ranitidine ?
Answer» Solution :CIMETIDINE or Ranitidine PREVENTS the interaction of histamine with the RECEPTORS present in stomach walls and therefore, secretion of acid is PREVENTED.

50.	How is acetone obtained from ethanol? Or How is acetic acid converted into acetone?
Answer» SOLUTION :.