51.

Which of the following compounds is most acidic?

• Cl-CH₂-CH₂-OH

• 

• 

• 

The reaction which involves dichlorocarbene as an electrophile is

• Reimer-Tiemann reaction

• Kolbe's reaction

• Friedel-Craft's acylation

• Fittig reaction

Ethanol is converted into ethoxy ethane,

• by heating excess of ethanol with conc. H₂SO₄ at 140°C

• by heating ethanol with excess of conc. H₂SO₄ at 443 K

• by treating with conc. H₂SO₄ at room temperature

• by treating with conc. H₂SO₄ at 273 K

An organic compound X is oxidised by using acidified K₂Cr₂O₇ solution. The product obtained reacts with phenyl hydrazine but does not answer silver mirror test. The compound X is,

• 2-propanol

• Ethanal

• Ethanol

• CH₃CH₂CH₃

Predict the product 'C' in the following series of reactions:

CH₃-COOH $\stackrel{{\mathrm{PCl}}_5}{\to } \mathrm{A} \underset{\mathrm{Anhy}. {\mathrm{AlCl}}_3}{\overset{{\mathrm{C}}_6{\mathrm{H}}_6}{\to }} \mathrm{B} \stackrel{{\mathrm{CH}}_3\mathrm{MgBr}}{\to } \mathrm{C}$

• 

• CH₃CH(OH)C₆H₅

• CH₃CH(OH)C₂H₅

• (CH₃)₂C(OH)C₆H₅

In the following sequence of reactions,

A $\stackrel{\mathrm{Reduction}}{\to } \mathrm{B} \stackrel{{\mathrm{HNO}}_2}{\to }$ CH₃CH₂OH

The compound A is

• propane nitrile

• ethane nitrile

• CH₃NO₂

• CH₃NC

Which of the following is not true?

• In vulcanisation, the rubber becomes harder and stronger

• Natural rubber has 'trans' configuration at every double bond

• Buna-S is a copolymer of butene and styrene

• Natural rubber is 1, 4-polymer of isoprene

Which of the following is a polyamide?

• Nylon-6, 6

• Terylene

• Polythene

• Buna - S

Which of the following is correct about H-bonding in DNA?

• A - T; G - C

• A - G; T - C

• G - T; A - C

• A - A; T - T

Which of the following is employed as a tranquiliser?

• Equanil

• Naproxen

• Tetracycline

• Dettol