Addition ofwater to alkynes occurs in acidic medium and in the presence of Hg²⁺ ions as a catalyst. Which of the following products will be formed on addition of water to but-1-yne under these conditions?

• CH₃CH₂CH₂CHO

• CH₃CH₂COCH₃

• CH₃CH₂COOH

• CH₃COOH + HCHO

Which one of these is not true for benzene?

• It forms only one type of mono-substituted product

• There are three carbon-carbon single bonds and three carbon-carbon double bonds

• Heat of hydrogenation of benzene is less than its theoretical value

• The bond angle between carbon-carbon bonds is 120°

CH₃CHO +HCHO $\underset{\mathrm{Heat}}{\overset{\mathrm{Dil}. \mathrm{NaOH}}{\to }}$ A $\underset{{\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{\mathrm{HCN}}{\to }}$ B

The structure of compound B is

Which of the following statement is correct ?

• +I group stabilises a carbocation

• +I group stabilises a carbanion

• -I group stabilises a carbocation

• -I group stabilises a free radical

Which of the following can give a Grignard reagent when reacted with magnesium in dry ether?

• C₂H₆

• C₂H₅Cl

• C₂H₅OH

• C₂H₅CN

t-butyl chloride preferably undergo hydrolysis by

• S_N1 mechanism

• S_N2 mechanism

• Any of (a) and (b)

• None of these

Iodoform gives a precipitate with AgNO₃ on heating but chloroform does not because

• C - I bond in iodoform is weak and C - Cl bond in chloroform is strong

• chloroform is covalent

• iodoform is ionic

• None of the above

238.

Which of the following undergoes nucleophilic substitution exclusively by S_N1 mechanism?

• Benzyl chloride

• Ethyl chloride

• Chlorobenzene

• lsopropyl chloride

Which of the following organic halogen compounds undergoes hydrolysis with aqueous NaOH predominantly by Sy1 mechanism?

• Ethyl iodide

• Methyl chloride

• lsopropyl chloride

• Benzyl chloride

Under basic condition which one suffers elimination the most?

• (CH₃)₃CCI

• (CH₃)₂CHCH₂CI

• CH₃CH₂CHCICH₃

• CH₃CH₂CH₂CH₂CI