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 will you prepare the following using Grignard reagent. (i) t-butyl alcohol (ii) allyl alcohol

Answer»

Solution :(i) `underset("(Grignard REAGENT)")(CH_(3)- MG - Br) + CH_(3) + CH_(3) underset("(Acetone)")(-overset(O)overset(||)(C)-C)H_(3) to CH_(3) - underset(CH_(3))underset(|)overset(OMgBr)overset(|)(C)-CH_(3) overset(H^(+)) underset(H_(2) O)(to) CH_(3) - overset(CH_(3))overset(|)underset(CH_(3))underset(|)(C)-OH + Mg Br(OH)`
(ii) `underset("(Grignard reagent)")(CH_2=CHMgBr) + underset(("Formaldehyde"))(H - overset(O)overset(||)C-H)tounderset(("ALLYL ALCOHOL"))underset(CH_2 = CH - CH_2OH + MgBr(OH))underset(darrH^(+)//H_2O)(CH_2=CH-CH_2-OMgBr)`
Discussion
2.

How will you prepare the following compounds from benzene ? PhCH_2CH_2CH_2Ph and

Answer»

SOLUTION :
Discussion
3.

How will you prepare the following compounds. (a) Hyponitrous acid (b) Nitrous acid (c ) Pernitrous acid (d) Pernitric acid

Answer»

Solution :(a) Hyponitrous acid : `Ag_(2)N_(2)O_(2)+2HClrarr 2AgCl+H_(2)N_(2)O_(2)`
(b) Nitrous acid : `Ba(NO_(2))_(2)+H_(2)SO_(4)RARR 2HNO_(2)+BaSO_(4)`
(c ) Pernitrous acid : `H_(2)O_(2)+ON(OH)rarr ON(OOH)+H_(2)O`
(d) Pernitric acid : `H_(2)O_(2)+N_(2)O_(5)rarr NO_(2)OOH+HNO_(3)`
Discussion
4.

How will you prepare the following compounds from benzene ? PhCH_2CH_2CH_2CH_2Ph

Answer»

SOLUTION :
Discussion
5.

Howwill youpreparethefollowing ? (a)n-Butanefrom ethylbromide . (b) Ethanefromaceticacid . ( c)Ethanefromethane . (d)Methanefromaceticacid . (e )Ethanefrommethanein twosteps. (f)Ethanefromethanolin onestep, ( g)Methyl chloridefromaluminumcarbide in twosteps. (h)propanefrommethane .

Answer»

Solution :`(a) C_(2)H_(5)Br+2Na+BrC_(2)H_(5)to C_(2)H_(5)-C_(2)H_(5)+2NaBr`
(B) `CH_(3)COOH+KOH to underset(CH_(3)-CH_(2))underset(darr "Electrolysis")CH_(3)COOK+H_(2)O`
`( C) C_(2)H_(4)+H_(2)underset(573K)overset(Ni)to C_(2)H_(6)`
`(D) CH_(3)COOH+NaOH to CH_(3)COONaunderset(CaO)overset(NaOH)to CH_(4)`
`( E) CH_(4)underset(hv)overset(Cl_(2))CH_(3)//Clunderset("Ether")overset(Na)to CH_(3)-CH_(3)`
`(f) C_(2)H_(5)OHoverset(P//HI)to C_(2)H_(6)`
`(G) Al_(4)C_(3)overset(H_(2)O)to CH_(4)underset(hv)overset(Cl_(2))to CH_(3)CL`
`(H)CH_(4)+Cl_(2)overset(hv)to CH_(4)underset( hv)to CH_(3)Cloverset(Na)to CH_(3)-CH_(3)underset(hv)overset(Cl_(2))to CH_(3)CH_(2)Cloverset(Li) overset( Cul) to Li(CH_(3)CH_(2))_(2)CUoverset(CH_(3)Cl)to CH_(3)CH_(2)CH_(3)`
Discussion
6.

How will you prepare sulphurdioxide by laboratory method?

Answer»

Solution :Sullphur dioxide is prepared in the laboratory treating a metal or metal sulphite with SULPHURIC acid.
`Cu+2H_(2)SO_(4)rarr CuSO_(4)+SO_(2)+2H_(2)O`
`SO_(3)^(-)+2H^(+)rarr H_(2)O+SO_(2)`
Discussion
7.

How will you prepare propan -1- amine from (i) Butane nitrile (ii) Propanamide (iii) 1- nitropropane

Answer»

Solution :(i) Pereparation of propan -1- amine from butane nitrile:
Butane bnitrile treated with acid hydrolysis FOLLOWED by Hoffmann.s bromamide degradation gives propan -1- amine
`UNDERSET(("Butane nitrile"))(CH_(3)-CH_(2)-CH_(2))-Cnoverset(H+//H_(2)O)(to) CH_(3)-underset(("Butanamide"))(CH_(2)-CH_(2))-CONH_(2)overset(Br_(2)//KOH)(to) CH_(3)-underset(("Propane-1-amine"))(CH_(2)-CH_(2)-NH_(2))`
(ii) Preparation of porpan-1-amine from propanamide:
when propanamide is treated with `LiAlH_(4)` in the presence of water gives propan -1- amine.
`underset(("Propanamide"))(CH_(3)CH_(2)CONH_(2))underset(H_(2)O)overset(LiAlH_(4))(to) underset(("Propan-1-amine"))(CH_(3)CH_(2)CH_(2)NH_(2))`
(iii) Preparation of propan -1- amine from 1- nitropropane:
`underset(("1-nitropropane"))(CH_(3)-CH_(2)-CH_(2))-NO_(2)underset(6(H))overset(Fe//HCl)(to) CH_(3)-underset(("Propan-1-amine"))(CH_(2)-CH_(2)-NH_(2))+2H_(2)O`
Reduction of 1-nitropropane using `H_(2)//NI` or Fe/HCl GIES propan -1- amine.
Discussion
8.

How will you prepare potassium permanganate from pyrolusite ore?

Answer»

Solution :Potassium permanganate is prepared from pyrolusite (MnO,) ore. The preparation involves the FOLLOWING steps.
(i) Conversion of `MnO_(2)` to potassium manganate:
Powdered ore is fused with KOH in the presence of air or oxidising agents like `KNO_(3)` . A green coloured potassium manganate is formed.
`2MnO_(2)+ 2KOH+ O_(2)to underset(underset("(Green)")("Potassium manganate"))(K_(2)MnO_(4))+ 2H_(2)O`
(ii) Oxidation of potassium manganate to potassium permanganate: Potassium manganate can be oxidised in two ways, either by chemical oxidation or electrolytic oxidation
(iii) Chemical oxidation: In this method potassium manganate is treated with ozone (`O_(3)`) or chlorine to get potassium permanganate,
`MnO_(4)^(2-)+ O_(3)+ H_(2)O to 2MnO_(4)^(-)+ 2OH^(-)+ O_(2)`
`2MnO_(4)^(2-)+ CI_(2) to 2MnO_(4)^(-) + 2CI^(-)`
(iv) Electrolytic oxidation: In this method aqueous solution of potassium manganate is electrolyzed in the presence of little ALKALI.
`K_(2)MnO_(4) hArr 2K^(+)+MnO_(4)^(2-)`
`H_(2)O hArr H^(+)+OH^(-)`
Manganate ions are converted into permanganate ions at anode.
`underset("(Green)")(MnO_(4)^(2-)) hArr underset("(purple)")(MnO_(4)^(-)) + e^(-)`
`H_(2)` is liberated at the cathode.
`2H^(+)+ 2e^(-) to H_(2)uarr`
The purple coloured solution is CONCENTRATED by evaporation and FORMS crystals of potassium permanganate on cooling.
Discussion
9.

How will you prepare propanal by oxoprocess?

Answer»

Solution :In oxoprocess, ETHENE is mixed WIT carbon monoxide and hydrogen GAS to PRODUCE propanal.
`CO+underset(("Ethene"))(C_(2)H_(4))+H_(2)tounderset(("Propanal"))(CH_(3)CH_(2)CHO)`
Discussion
10.

How will you prepare phosphine and explain the purification of phosphine?

Answer»

Solution :Phosphine is prepared by action of sodium hydroxide with white phosphorous in an inert ATMOSPHERE of carbon of hydrogen.
`P_(4)+3NaOH+3H_(2)Orarr underset("sodium hypo phosphite")(3NaH_(2)PO_(2))+underset("Phosphine")(PH_(3)uarr)`
Phosphine is freed from phosphine DIHYDRIDE `(P_(2)H_(4))` by passing through a freezing mixture. The dihydride condenses while phosphine does not.
Phosphine can also prepared by the hydrolysis of METALLIC phosphides with water of dilute mineral acids.
`Ca_(3)P_(2)+6H_(2)Orarr underset("Phosphine")(2PH_(3)uarr)+3Ca(OH)_(2)`
`AlP+3HClrarr underset("Phosphine")(PH_(3)uarr)+AlCl_(3)`
Phosphine is prepared in pure form by heating phosphorous acid.
`underset("Phosphorous acid")(4H_(3)PO_(3))overset(Delta)RARR underset("Ortho phosphoric acid")(3H_(3)PO_(4))+underset("Phosphine")(PH_(3)uarr)`
A pure sample of phosphine is prepared by heating phophonium iodide with caustic soda solution.
`PH_(4)I+NaOH overset(Delta)rarr underset("Phosphine")(PH_(3)uarr)+NaI+H_(2)O`
Discussion
11.

How will you prepare potash alum?

Answer»

Solution :The alunite the alum STONE is the naturally OCCURING form and it is `K_(2)SO_(4).Al_(2)(SO_(4))_(3).4Al(OH)_(3)`
When alum stone is treated with excess of sulphuric acid, the aluminium hydroxide is converted to aluminium sulphate. A calculated quality of potassium sulphate is added and the solution is crystallised to generate potash alum. ITIS purified by recrystallisation.
`K_(2)SO_(4).Al_(2)(SO_(4))_(3).4Al(OH)_(3)+6H_(2)SO_(4)toK_(2)SO_(4)+Al_(2)(So_(4))_(3)+12H_(2)O`
`K_(2)SO_(4)+Al_(2)(SO_(4))_(3)+24H_(2)OtoK_(2)SO_(4).Al_(2)(SO_(4))_(3).24H_(2)O`
Discussion
12.

How will you prepare phenol (i) From chloro benzene (ii) From benzene sulphonic acid?

Answer»

Solution :(i) From halo arenes (Dows process):
When Chlorobenzene is hydrolysed with `6-8%` of NAOH at 300 bar and 633 K in a closed VESSEL, sodium phenoxide is formed which on treatment with dilute HCl gives PHENOL.

(ii) From benzene sulphonic acid:
Benzene is sulphonated with oleum and the benzene sulphonic acid so formed is heated with motlen NaOH at 623 K gives sodium phenoxide which on acidification gives phenol.
Discussion
13.

How will you prepare phosphine and explain the purification of phosphine ?

Answer»

Solution :Phosphine is prepared by action of sodium HYDROXIDE with white phophorous in an inert atmosphere of carbon dioxide or hydrogen.
`P_(4) + 3NaOH + 3H_(2) O rarr underset("sodium hypo phosphite")(3NaH_(2)PO_(2)) + underset("Phosphine")(PH_(3) UARR)`
Phosphine is freed from phosphine dihydride `(P_(2)H_(4))` by passing through a freezing mixture. The dihydride condenses while phosphine does not.
Phosphine can also prepared by the hydrolysis of metallic phosphides with water or dilute mineral acids.
`{:(Ca_(3)P_(2) + 6H_(2)O,rarr,underset("Phosphine")(2PH_(3)uarr) + 3Ca(OH)_(2)),(AIP + 3HCI,rarr,underset("Phosphine")(PH_(3) uarr) + AlCl_(3)):}`
Phosphine is prepared in PURE form by heating phosphorous acid.
`underset("Phosphorous acid")(4H_(3)PO_(3)) overset(Delta)rarr underset("Ortho phosphoric acid")(3H_(3)PO_(4)) + underset("Phosphine")(PH_(3) uarr)`
A pure sample of phosphine is prepared by heating phosphine IODIDE with caustic soda solution.
`PH_(4)I + NaOH overset(Delta)rarr underset("Phosphine")(PH_(3) uarr) + NaI + H_(2)O`
Discussion
14.

How will you prepare PHBV? Give its use?

Answer»

Solution :(i) The biodegrable polymer PHBV (Poly hydroxy butyrate-co hydroxyl valerate) is prepared by the polymerisation of monomers 3 - hydroxy butanoic acid and 3 - hydroxy pentanoic acid.
`nCH_(3) - underset(OH)underset(|)(CH) -CH_(2)-COOH + n CH_(3) - CH_(2) -underset(OH)underset(|)(CH) -CH_(2) -COOH overset(-H_(2)O)to [-O-underset(CH_(3))underset(|)(CH)-CH_(2) - underset(O) underset(||)C -O - underset(CH_(2)-CH_(3))overset(CH_(2)-CH_(2))(|) -overset(C)underset(O)(||)-]_(n)`
(ii) It is USED in orthopaedic DEVICES and in controlled release of drugs.
Discussion
15.

How will you prepare orthophosphoric acid from phosphorous?

Answer»

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Solution :Whenphosphorous is treated with conc. Nitric acid it is oxidised to orthophosphoric acid.
This reaction is catalysed by iodine CRYSTALS.
`P_(4)+20HNO_(3)OVERSET(I_(2))underset("(ortho phosphorous acid)")rarr 4H_(3)PO_(4)+20NO_(2)+4H_(2)O`
Discussion
16.

How will you prepare PCl_(3)?

Answer»

Solution :When `PCl_(3)` is TREATED with EXCESS chlorine, PHOSPHOROUS pentachloride is obtained.
`PCl_(3)+Cl_(2)rarrPCl_(5)`
Discussion
17.

How will you prepare p-dinitrobenzene from p-nitroaniline?

Answer»

SOLUTION :
Discussion
18.

How will you prepare Nylon-6? Give its use.

Answer»

Solution :(i) Capro tactum on heating at 533k in an inert atmosphere with TRACES of water gives E amino caproic acid which polymerises to give NYLON 6.

(iii) It is used in the manufacture of TYRE CARDS, FABRICS
Discussion
19.

How will you prepare ozone by laboratory method? Explain the structure of ozone.

Answer»

Solution :In the laboratory ozone is prepared by passing electrical discharge through oxygen. At a potential of 20,000 V about `10%` of oxygen os converted into ozone it GIVES a mixture known as ozonised oxygen. Pure ozone is obtained as a PALE BLUE gas by the fractional distillation of liquefied ozonised oxygen.
`UNDERSET("(oxygen)")(O_(2))hArr underset("(atomic oxygen)")(2(O))`
`O_(2)+(O)hArr underset("(ozone)")(O_(3))`

Structure of ozone : The ozone molecule have a bent shape and symmetrical with delocalised bonding between the oxygen atoms.
Discussion
20.

How will you prepare Nylon 6,6.? Give its use.

Answer»

SOLUTION :(i) Nylon 6,6 can be prepared by MIXING equimolar adipic acid and hexamethylene diamine. With the elimination of water to FORM AMIDE bonds.

(iii)It is usedin textiles , MANUFACTURE of cards .
Discussion
21.

How will you prepare nitrogen pentoxide?

Answer»

Solution :NITRIC acid REACTS with phosphorous pentaoxide to GIVE nitrogen pentoxide.
`2HNO_(3)+P_(2)O_(5)rarrN_(2)O_(5)+2HPO_(3)`
Discussion
22.

How will you prepare nitric acid?

Answer»

Solution :Nitric acid prepared by heating EQUAL AMOUNTS of POTASSIUM or sodium nitrate with CONCENTRATED sulphuric acid.
`KNO_(3)+H_(2)SO_(4)rarrKHSO_(4)+HNO_(3)`
The temperature is kept as low as possible to avoid decomposition of nitric acid. The acid condennses to a fuming liquids which is coloured brown by the presence of a little nitrogen dioxide which is formed DUE to the decomposition of nitric acid.
`4HNO_(3)rarr 4NO_(2)+2H_(2)O+O_(2)`
Discussion
23.

How will you prepare nitric oxide from sodium nitrite?

Answer»

Solution :When sodium nitrite reacts with ferrous SULPHATE in the presence of sulphuric acid to gives nitrix OXIDE.
`2NaNO_(2)+2FeSO_(4)+3H_(2)SO_(4)rarr Fe_(2)(SO_(4))_(3)+2NaHSO_(4)+2H_(2)O+2NO`
Discussion
24.

How will you prepare nitric acid by Ostwald's process?

Answer»

Solution :Nitric acid prepared in large scales using Ostwald.s process. In this method ammonia from Haber.s process is mixed about 10 times of air. This mixture is preheated and PASSED into the CATALYST chamber where they come in contactwith platinum gauze. The temperature rises to about 1275 K and metallic gauze brings about the rapid catalytic oxidation of ammonia resulting in the formation of `NO`, which then oxidised to NITROGEN dioxide.
`4NH_(3)+5O_(2)rarr 4NO+6H_(2)O+120kJ`
`2NO+O_(2)rarr 2NO_(2)`
The nitrogen dioxide produced in passed through a series of ADSORPTION towers. It reacts with water to give nitric acid. Nitric acid FORMED is bleached by blowing air.
`6NO_(2)+3H_(2)Orarr 4HNO_(3)+2NO+H_(2)O`
Discussion
25.

How will you prepare methanol from formaldehyde without using a reducing agent.

Answer»

Solution :CANNIZZARO reaction is a DISPROPORTIONATION reaction in which one molecule of an aldehyde is reduced while the other is oxidised.
`underset("Formaldehyde")(2H-overset(O)overset(||)(C)-H) + underset((50%))(NaOH)to underset("METHANOL")(CH_(3)OH)+underset("Sod. formate")(HCOONa)`
Here, a CONC. solution NaOH is used which is not a reducing agent.
Discussion
26.

How will you prepare malachite green dye from Benzaldehyde?

Answer»

Solution :Benzaldehyde condenses with TERTIARY aromatic amines LIKE N, N - DIMETHYL aniline in the presence of strong ACIDS to triphenyl methane DYE.
Discussion
27.

How will you prepare hydrochloric acid by laboratory method?

Answer»

Solution :It is prepared by the ACTION of sodium chloride and concentrated sulphuric acid.
`NaCl+H_(2)SO_(4)rarr NaHSO_(4)+HCl`
`NaHSO_(4)+NaClrarr Na_(2)SO_(4)+HCl`
Dry HYDROCHLORIC acid is obtained by passing the gas through conc. Sulphuric acid.
Discussion
28.

How will you prepare ethylbenzene be using ethyne as the only organic substance and any other inorganic substance of your choice ?

Answer»

SOLUTION :Ethylbenzene `(C_(6)H_(5)C_(2)H_(5))`
Discussion
29.

How will you prepare haloalkane from alcohol and hydrocarbon ? Write one chemical reaction of each.

Answer»

Solution :(a) From Alcohol (By the action of `PCI_(5)`)
e.g. `C_(2)H_(5)OH + PCI_(5) toC_(2)H_(5)CL + HCl + POCI_(3)`
(b) From hydrocarbon (Alkanes) (By DIRECT halogenation)
e.g `CH_(4)+ Cl_(2) overset(hv)to underset("Methyl CHLORIDE")(CH_(3)Cl)+ HCl`
Discussion
30.

How will you prepare ethyl amine from methyl iodide ?

Answer»

Solution :Methyl iodide REACTS with KCN to GIVE methyl cyanide which is REDUCED by Na/alcohol to get ethyl AMINE.
`underset(METHYL IODIDE)(CH_3-I) OVERSET KCNrarr underset(Methyl cyanide) (CH_3-CN)overset(4H)rarrunderset(Ethylamine)CH_3-CH_2-NH_2`
Discussion
31.

How will you prepare ethyl amine from- (i) ethyl iodide (ii) phthalimide (iii) acetaldoxime (iv) acetonitrile?

Answer»

SOLUTION :(i) ETHYL iodide: When ethyl iodide is heated with excess of alcoholic ammonia, under pressure at 373 K ethanamine is obtained as a major product.
`underset("ethyl iodide")(CH_(3)-CH_(2))-I+ underset("ammonia")underset("excess")underset(("alc."))(NH_(3))overset(Delta)(to) CH_(3)-underset("ethanamine")(CH_(2)-NH_(2))+HI`
(ii) PHTHALIMIDE: Phthalimide is REACTED with alcoholic KOH to form potassium phtalimide. Further potassium phthalimide is treated with an ethyl iodide. The produce N-ethylphthalimide is hydrolysed wilth dilte HCl to form ethyl amine. This reaction is known Garbiel phthalimide synthesis.

(iii) Acetaldoxime: AScetaldoxime on reduction with `Na` and alcohol forms ethylamine.
`underset("acetaldoxime")(CH_(3)-overset(H)overset(|)(C)=N-)OH+4[H] underset(Delta)overset(Na//"ethanol")(to)CH_(3)-underset("ethyl amine")(CH_(2)-NH_(2)+H_(2)O`
(iv) Acetonitrile: Methyl cyanide or acetonitrile on reduction by sodium and ethyl alcohol forms ethanamine. The reaction is called Mendius reduction.
`underset("or methyl cyanide")underset("acetonitrile")(CH_(3)-C-=)N+4[H]overset(Na//"alcohol")(to)underset("or ethanamine")underset("ethylamine")(CH_(3)-CH_(2))-NH_(2)`
Discussion
32.

How will you prepare ethanol, propan-2-ol-and 2-methyl propane-2-ol from Grignard's reagent ? Define optical activity. Explain optical activity of lactic acid.

Answer»

SOLUTION :(a)
(b)
(ii)Optical activity : When plane POLARISED light is passed through a solution of certain organic substance like glucose lactice acid etc. The plane polarised light gets rotated through a certain angle. This property or phenomenon of certain organic substance to rotate the plane plarised light towards right or towards left is called optical activity.
(III) Optical activity of lactiv acid :
`H-underset(("Latic acid"))underset(CH_(3))underset(|)overset(COOH)overset(|)(C^(**))-OH` cotains only one asymmetric carbon atom
The number of optically active isomers, possibel depends on number of ASYMMETRICAL carbon atom As `2^(n)` where n=no. of asymmetric carbon atom thus for LACTIC acid, n=1 thus two optical isomers possible.
Discussion
33.

How will you prepare colloidal solution of sulphur?

Answer»

SOLUTION :By PASSING `H_2S`GAS through abromine WATER :
` H_2S+ Br_2 to 2HBR + S`
Discussion
34.

How will you prepare colloidal solution of gold?

Answer»

SOLUTION :By REDUCTION of `AuCl_3` with `SnCl_2` or by Bredig.s ARC METHOD.
Discussion
35.

How will you prepare colloidal solution of gold ?

Answer»

Solution :By BREDIG's electrodisintegration METHOD or by reduction of `AuCl_(3)` with `SnCl_(2)` solution.
Discussion
36.

How will you prepare Cl_2 from NaCl ?

Answer»

Solution :CHLORINE can be PREPARED by electrolysing NaCl solution when `Cl_2` is EVOLVED at ANODE.
Discussion
37.

How will you preparechlorine in the laboratory?

Answer»

Solution :(i) Chlorine is prepared by the ACTION of conc. Sulphuric acid on chlorides in presence of manganeses dioxide.
`4NaCl+MnO_(2)+4H_(2)SO_(4)rarr Cl_(2)+MnCl_(2)+4NaHSO_(4)+2H_(2)O`
(ii) It can ALSO be prepared by oxidising hydrochloric acid using various oxidising agents such as manganese dioxide, potassium permanganate or dichromate.
`PbO_(2)+4HClrarr PbCl_(2)+2H_(2)O+Cl_(2)`
`MnO_(2)+4HClrarr MnCl_(2)+2H_(2)O+Cl_(2)`
`2KMnO_(4)+16HClrarr 2KCl+2MnCl_(2)+8H_(2)O+5Cl_(2)`
`K_(2)Cr_(2)O_(7)+14HCl rarr 2KCl +2CrCl_(3)+7H_(2)O+3Cl_(2)`
(iii) When BLEACHING power is TREATED with mineral acids chlorine is liberated
`CaOCl_(2)+2HClrarr CaCl_(2)+H_(2)O+Cl_(2)`
`CaOCl_(2)+H_(2)SO_(4)rarr CaSO_(4)+H_(2)O+Cl_(2)`
Discussion
38.

How will you prepare chlorine in the laboratory ?

Answer»

Solution :(i) Chlorine is prepared by the ACTION of conc. Sulphuric acid on chlorides in presence of manganese dioxide.
`4NaCl+MnO_(2)+4H_(2)SO_(4) rarr Cl_(2)+MnCl_(2)+4NaHSO_(4)+2H_(2)O`
(ii) It can also be prepared by OXIDISING hydrochloric acid using various oxidising AGENTS such as manganese dioxide, lead dioxide, potassium permanganateor dichromate.
`PbO_(2)+4HCl rarr PbCl_(2)+2H_(2)O+Cl_(2)`
`MnO_(2)+4HCl rarr MnCl_(2)+2H_(2)O+Cl_(2)`
`2KMnO_(4)+16HCl rarr 2KCl +2MnCl_(2)+8H_(2)O+5Cl_(2)`
`K_(2)Cr_(2)O_(7)+14HCl rarr 2KCl+2CrCl_(3)+7H_(2)O+3Cl_(2)`
(iii) When bleachingpowder is treated with mineral acids acids chlorine is liberated
`CaOCl_(2)+2HCl rarr CaCl_(2)+H_(2)O+Cl_(2)`
`CaOCl_(2)+H_(2)SO_(4) rarr CaSO_(4)+H_(2)O+Cl_(2)`
Discussion
39.

How will you prepare Butan-2-0l from ethanal? (or) Convert Ethyl Magnesium bromide into 2-Butanol (or) Starting from acetaldehyde, how would you obtain butan-2-ol?

Answer»

SOLUTION :`underset("bromide")underset("ETHYL MAGNESIUM")(CH_3-CH_2MgBr)+underset("Acetaldehyde")underset("Ethanal(or)")(CH_3CHO)overset("Ether")toCH_3-CH_2-underset(H)underset(|)overset(CH_3)overset(|)C-OMgBr overset(H_2O //H^(+))toCH_3-underset("Butan - 2-ol")(CH_2-underset(OH)underset(|)(CH)-CH_3)`
Discussion
40.

How will you prepare (CH_3)_2CD^(14)CH_3 from propane (CH_3CH_2CH_3)?

Answer»

SOLUTION :
Discussion
41.

How will you prepare butan-1-ol from (i) 1-bromobutane and (ii) a suitable alkene?

Answer»

SOLUTION :(i) `underset("1-Bromobutane")(CH_(3)CH_(2)CH_(2)CH_(2)BR)+KOH(AQ)rarr underset("Butan-1-ol")(CH_(3)CH_(2)CH_(2)CH_(2)OH)+KBr`
(ii) `underset("But-1-ene")(6CH_(3)-CH_(2)-CH)=underset("DIBORANE")(CH_(2)+B_(2)H_(6))rarr 2(CH_(3)-CH_(2)-CH_(2)-CH_(2))_(3)B overset(H_(2)O_(2))underset(OH^(-))rarr underset("Butan-1-ol")(6CH_(3)CH_(2)CH_(2)CH_(2)OH)+H_(3)BO_(3)`
Discussion
42.

How will you prepare benzoic acid using Grignard reagent.

Answer»

Solution :Preparation of BENZOIC ACID USING Grignard REAGENT :
Discussion
43.

How will you prepare benzene from the given compounds? (iv) C_6H_5CMe_3

Answer»

SOLUTION :
Discussion
44.

How will you prepare benzaldehyde from methyl benzene? (or) Explain Etard reaction.

Answer»

SOLUTION :When chromylchloride is used as an oxidising AGENT, toluene GIVES benzaldehyde. This reactiou is called Etard reaction. Acetic anhydride and `CrO_3`can also be used for this reaction.
Discussion
45.

How will you prepare benzaldehyde by Gatterman-Koch reaction?

Answer»


ANSWER :REFER to THEORY
Discussion
46.

How will you prepare benzaldehyde by Etard's reaction?

Answer»


Answer :Toluene is treated with `CrO_3` in acetic ANHYDRIDE and then hydrolysed (SEE theory for EQUATION)
Discussion
47.

How will you prepare ammonia from nitrogen? And mention the name of process?

Answer»

Solution :Nitrogen directly REACTS with hydrogen gives ammonia. This reaction is favoured by HIGH pressures and at optimum temperature in the PRESENCE of iron catalyst.
`N_(2)+3H_(2)hArr 2NH_(3)`
This process is called as Haber.s process.
Discussion
48.

How will you prepare amines from the following ? Write then chemical reactions. (i) R CO NH_2 "" (ii) RX ""(iii) R-C-=N

Answer»

Solution :(i) `R CO NH_2 + 4(H) OVERSET(Zn + "Cone HCl")to R CH_2NH_2 + H_2 O`
(ii) `RX + underset("(ALC)")(NH_3) overset(DELTA)to RNH_2 + HX`
(iii) `R CN + 4(H) overset(Na//"alc")to R CH_2 NH_2`
Discussion
49.

How will you prepare : a pure sample of a primary amine from a primary alkyl halide

Answer»

SOLUTION :By GABRIEL SYNTHESIS
Discussion
50.

How will you prepare : a primary amine from an amide ?

Answer»

SOLUTION :REDUCTION with `H_2 //NI`
Discussion