31.

The extraction of which of the following metals involves bessemerisation?

• Fe

• Ag

• Al

• Cu

Le-blanc process is employed in the manufacture of

• baking soda

• washing soda

• potash

• plaster of Paris

The number of atoms contained in a fee unit cell of a monoatomic substance is

• 1

• 2

• 4

• 6

In the first order reaction, 75% of the reactant gets disappeared in 1.386 h. The rate constant of the reaction is

• 3.0 $\times$10^-3 s^-1

• 2.8 $\times$ 10 ^-4 s^-1

• 17.2 $\times$ 10^-3 s^-1

• 1.8 $\times$ 10^-3 s^-1

CH₃COOH $\stackrel{{\mathrm{Br}}_2/ \mathrm{P}}{\to }$ Y $\underset{\left(\mathrm{ii}\right) {\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{\left(\mathrm{i}\right) \mathrm{KCN}}{\to }}$ X

Here, X is

• glycollic acid

• $\mathrm{\alpha }$-hydroxy propionic acid

• succinic acid

• malonic acid

Which of the following is most basic in nature?

• NH₃

• CH₃NH₂

• (CH₃)₂NH

• C₆H₅N(CH₃)₂

An example of natural biopolymer is

• teflon

• nylon-66

• rubber

• DNA

Which of the following is known as invert soap?

• Pentaerythritol monostearate

• Sodium stearyl sulphate

• Trimethyl stearyl ammonium bromide

• Ethoxylated nonyphenol

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