MCQ
Which oxide will not given metal on heating:-
- A$HgO$
- ✓$ZnO$
- C$Ag_2O$
- DAll of these
✓
Answer
Correct option: B.
$ZnO$
b
Metals lying above $H$ in electrochemical series are not obtained from their oxides by heating.
Metals lying above $H$ in electrochemical series are not obtained from their oxides by heating.
On heating, $ZnO$ will not give $Zn$ metal.
However, it can be reduced with C or hydrogen to give free metal.
$ZnO + C \rightarrow Zn +[ CO ]$
$ZnO +[ CO ] \rightarrow Zn + CO _2$
$ZnO + H _2 \stackrel{\text { above } 400^{\circ} C }{\longrightarrow} Zn + H _2 O$
However, $HgO$ and $Ag _2 O$ on heating will give $Hg$ and $Ag$ respectively.
$2 HgO \rightarrow 2 Hg + O _2$
$2 Ag _2 O \rightarrow 4 Ag + O _2$
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