Question

Which of the following options are correct regarding the manufacture of $H_2{SO}_4$ by Contact process?

The statements given below are regarding the contact process for the manufacture of $H_2{SO}_4$.
(a) Manufacture of ${SO}_2$ from sulphur is a reversible process.
(b) High pressure, optimum temperature and specific catalyst is required to obtain a better yield of ${SO}_3$.
(c) ${SO}_3$ is hydrolysed to get $H_2{SO}_4$.
(d) Pyrosulphuric acid is hydrolysed to get $H_2{SO}_4$.

• A. $a$ and $d$
• B. $b$ and $c$
• C. only $d$
• D. $b$ and $d$
  

Answer 1

The correct option is D $b$ and $d$

Sulphur dioxide is produced by burning sulphur in excess of oxygen.

$S$ $+$ $O_2$ $\underrightarrow{\Delta }$ $S{O}_2$

Since combustion reactions are irreversible, (a) is incorrect.

$S{O}_3$ is produced by burning $S{O}_2$ in oxygen

$2S{O}_2\left(g\right)$ $+$ $O_2\left(g\right)$ $\underrightarrow{\Delta }$ $2S{O}_3\left(g\right)$

Since less number of molecule are there in the produced side than the reactant side, low temp, high pressure and a specific Catalyst like Pt. is required to produce maximum amount of $S{O}_3$

So (b) is correct.

In Contact Process, $H_2{S}_2{O}_7$ is hydrolysed to produced $H_{2}S{O}_4$

$H2S_2{O}_7$ $+$ $H_{2}O$ $⟶$ $2H_{2}S{O}_4$

Hence (c) is incorrect and d is correct.