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Q.
The amount of metallic $Zn$ (atomic weight $=65.4$ ) required to react with aqueous sodium hydroxide to produce $1 \,g$ of $H _{2}$, is
KVPYKVPY 2013
Solution:
$Zn +2 NaOH (a q) \longrightarrow Na _{2} ZnO _{4}+ H _{2} \uparrow$
$1$ mole of $H _{2}$ is produced by $1$ mole of $Zn$,
i.e. $2 \,g$ of $H _{2}$ is produced by $65.4\, g$ of $Zn$
$\therefore 1 \,g$ of $H _{2}$ is produced by
$=\frac{65.4}{2} g =32.7\, g$