31.

Steel is heated to below red heat and then, cooled slowly. The process refers to

• hardening

• annealing

• tempering

• nitriding

Which of the following reagents converts both acetaldehyde and acetone to alkanes ?

• Ni/H₂

• LiAlH₄

• I₂/ NaOH

• Zn-Hg/ conc. HCl

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

The reaction,

C₆H₅CHO + CH₃COOC₂H₅ $\to$ C₆H₅CH = CHCOOC₂H₅ , is called

• Benzoin condensation

• Claisen condensation

• Cannizaro's reaction

• Perkin reaction

The best method to separate the mixture of ortho and para nitrophenol (1 : 1) is

• vaporisation

• colour spectrum

• distillation

• crystallisation

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

Which one of the following reactions is called Rosenmund reaction ?

• Aldehydes are reduced to alcohols

• Acids are converted to acid chlorides

• Alcohols are reduced to hydrocarbons

• Acid chlorides are reduced to aldehydes

During, acetylation of amines, what is replaced by acetyl group ?

• Hydrogen atom attached to nitrogen atom

• One or more hydrogen atoms attached to carbon atom

• One or more hydrogen atoms attached to nitrogen atom

• Hydrogen atoms attached to either carbon atom or nitrogen atom

Which is used in alcoholic beverages ?

• Methanol

• Ethanol

• Phenol

• Glycerol