21.

Pick out the wrong statement.

• Nitrogen has the ability to form p-p bonds with itself

• Bismuth forms metallic bonds in elemental state

• Catenation tendency is higher in nitrogen when compared with other elements of the same group

• Nitrogen has higher first ionization enthalpy when compared with other elements of the same group

The wrong statement about the interstitial compounds is

• their melting points are lower than those of pure metals

• they retain metallic conductivity

• they are chemically inert

• their bonds are neither ionic non covalent

In the estimation of sulphur by Carius method, 0.480 g of an organic compound gives 0.699 g of barium sulphate. The percentage of sulphur in this compound is (Atomic masses Ba = 137, S = 32, O = 16)

• 20%

• 15%

• 35%

• 30%

The least stable free radical is

• CH_{32$\stackrel{.}{\mathrm{C}}$H}

• $\stackrel{.}{\mathrm{C}}$H₃

• (CH₃)₂$\stackrel{.}{\mathrm{C}}$H

• (CH₃)₃$\stackrel{.}{\mathrm{C}}$

Which one of the following reactions proceeds through free radical chain mechanism?

• Addition of HBr on ethene

• Halogenation of benzene in the presence of FeBr₃

• Photochemical chlorination of methane

• Hydrolysis of tert-butyl chloride with aqueous KOH

Which one of the following is the correct statement?

• Achiral molecules are superimposable

• Alanine is optically inactive amino acid

• Glycine is optically active amino acid

• There is inversion when (-)-2-methylbutan-1-ol is heated with conc. HCl to form (+)-1-chloro-2-methylbutane

When HBr adds on hex-1-ene in the presence of benzoyl peroxide, the product is

• 2-bromohexane

• 2, 3-dibromohexane

• 1-bromohexane

• 2, 4-dibromohexane

The decreasing order of boiling points of alkyl halides is

• RF > RCl > RBr > RI

• RBr > RCl > RI > RF

• RI > RBr > RCl > RF

• RCl > RF > RI > RBr

The correct order of ease of cleavage of ether linkage by hydrogen halide follows

• HI > HBr > HCl

• HBr > HI > HCl

• HCl > HBr > HI

• HCl > HI > HBr

What are the starting materials to get 2-methylpropene as the major product?

• Sodium methoxide and sec-butyl bromide

• Sodium ethoxide and sec-butyl bromide

• Sodium tert-butoxide and ethyl bromide

• Sodium methoxide and tert-butyl bromide