Which of the following reaction is an example of autoreduction?

Options

A. `Fe_3O_4 + 4CO rarr 3Fe + 4CO_2`
B. `Cu_2O + C rarr 2Cu + CO`
C. `Cu^(2+)(aq) + Fe(S) rarr Cu(s) + Fe^(2+)(aq)`
D. `Cu_(2)O + (1)/(2) Cu_(2)S rarr 3Cu + (1)/(2)SO_2`

Answer

D

Explanation

`Cu_(2)O + (1)/(2) Cu_(2)S rarr 3Cu + (1)/(2) SO_(2)`
This reaction includes reduction of copper (I) oxide by copper (I) sulphide. In this process, copper is reduced by itself hence this process is known as autoreduction and the solidified copper, so obtained, is known as blister copper.