$5 \ g$ of zinc is treated separately with an excess of
$(a)$ dilute hydrochloric acid and
$(b)$ aqueous sodium hydroxide.
The ratio of the volumes of $H_{2}$ evolved in these two reactions is:

$A$ sample of $CaCO_3$ and $MgCO_3$ weighing $2.21 \ g$ is ignited to a constant weight of $1.152 \ g$. The composition of the mixture is:
(Given molar mass in $g \ mol^{-1}: CaCO_3 = 100, MgCO_3 = 84$)

What is the volume (in litres) of oxygen required at $STP$ to completely convert $1.5 \ mol$ of sulphur into sulphur dioxide?

If the density of methanol is $0.793 \ kg \ L^{-1}$,what volume is needed to prepare $2.5 \ L$ of a $0.25 \ M$ solution (in $mL$)?

$10 \ mol$ of a mixture of hydrogen and oxygen gases at a pressure of $1 \ atm$ at constant volume and temperature,react to form $3.6 \ g$ of liquid water. The pressure of the resulting mixture will be closest to $..... \ atm$

$12 \ g$ of $Mg$ (atomic mass $24$) on reacting completely with acid gives hydrogen gas,the volume of which at $STP$ would be ............... $L$.