Question

a) How is chlorine prepared in Deacon's process? How does it react with the following?
i) Cold and dilute NaOH
ii) Hot and concentrated NaOH
b) Give chemical equations to manufacture of Sulphuric Acid by contact process.

Answer 1

a) Preparation of chlorine in Deacon's process:
Atmospheric oxygen oxidizes HCl gas in presence of cupric chloride catalyst to form chlorine. Temperature is 723 K.
$4Cl+O_2\stackrel{CuC{l}_2}{\to }2C{l}_2+2H_{2}O$
The reactions of chlorine:
i) Cold and dilute NaOH:
Sodium chloride and sodium hypochloride are formed.
$C{l}_2+2NaOH\to NaCl+NaOCl+H_{2}O$
ii) Hot and concentrated NaOH:
Sodium chloride and sodium chlorate are obtained.
$3C{l}_2+6NaOH\to 5NaCl+NaCl{O}_3+3H_{2}O$
b) Chemical equations to manufacture of sulphuric acid by contact process:
$S+O_2\to S{O}_2$
$4Fe{S}_2+11O_2\to 2F{e}_2{O}_3+8S{O}_2$
$2S{O}_2+O_2\stackrel{V_2{O}_5}{\to }2S{O}_3$
$S{O}_3+H_{2}S{O}_4\to H_2{S}_2{O}_7\cdot S{O}_3$
$H_2{S}_2{O}_7+H_{2}O\to 2H_{2}S{O}_4$