21.

Among the following, the ambident nucleophile is

• iodide

• alkoxy

• hydroxyl

• cyanide

Out of the following isomeric alcohols containing five carbon atoms, the alcohol that exhibits optical isomerism is

• 1-pentanol

• 2-pentanol

• 3-pentanol

• 2-methyl-2-butanol

An odd electron molecule among the following is

• CO

• SO₂

• CO₂

• NO

Which one of the following is reduced by H₂O₂ in alkaline medium?

• Fe²⁺

• HOCl

• KMnO₄

• PbS

Aluminium (atomic mass = 27) crystallises in a cubic system with edge length of 4 Å. Its density is 2. 7 g cm^-3 The number of aluminium atoms present per unit cell is

• 5

• 6

• 4

• 2

For two isomorphous crystals A and B, the ratio of density of A to that of B is 1.6 while the ratio of the edge length of B to that of A is 2. If the molar mass of crystal B is 200 g mol^-1, then that of crystal A is

• 240 g mol^-1

• 40 g mol^-1

• 80 g mol^-1

• 160 g mol^-1

A binary solid has a primitive cubical structure with B^- ions constituting the lattice points and A⁺ ions· occupying 25% of its tetrahedral holes. The molecular formula of the crystal is

• A₂B

• AB₃

• AB₂

• A₂B₃

Match the following-

• A - r; B - p; C - t; D - q; E - s

• A - t; B - s; C - q; D - p; E - r

• A - t; B - r; C - q; D - p; E - s

• A - t; B - s; C - q; D - r; E - p

In the metallurgy of zinc; the reducing agent employed in reducing the zinc oxide to crude zinc metal in the last stage is

• Al

• Li

• Coke

• Water gas

Which one of the following has the maximum number of P-OH bonds?

• H₃PO₂

• H₃PO₄

• H₄P₂O₆

• H₄P₂O₅