Question

Upon heating with $C{u}_{2}S$, the reagents that give copper metal is/are

• A. $CuFe{S}_2$
• B. $CuO$
• C. $C{u}_{2}O$
• D. $CuS{O}_4$

Answer 1

Answer: (B), (C), (D)

The correct options are
B $CuO$
C $C{u}_{2}O$
D $CuS{O}_4$

The trick is to get to Copper (I) oxide, which undergoes self-reduction:
During self reduction,
$2C{u}_{2}O+C{u}_{2}S\stackrel{\Delta }{\to }6Cu+S{O}_2$

For this to happen, look for compounds that eventually lead to $C{u}_{2}O$:

This reaction is characteristic of Copper (II) Oxide:
$4CuO\stackrel{1373K}{\to }2C{u}_{2}O+O_2$

Also, Copper (II) Sulphate on heating gives Copper (II) oxide:
$2CuS{O}_4\stackrel{1093K}{\to }2CuO+2S{O}_2+O_2$