What will be the molality of the solution containing $18.25 \mathrm{~g}$ of $\mathrm{HCl}$ gas in $500…
What will be the molality of the solution containing $18.25 \mathrm{~g}$ of $\mathrm{HCl}$ gas in $500 \mathrm{~g}$ of water?
$0.5 \mathrm{~m}$
) $0.1 \mathrm{~m}$
$1 \mathrm{~m}$
$0.05 \mathrm{~m}$
Solution
Given, mass of $\mathrm{HCI}=18.25 \mathrm{~g}$
Molar mass of $\mathrm{HCI}=36.5 \mathrm{~g} / \mathrm{moI}$
Mass of water $=500 \mathrm{~g}=0.5 \mathrm{~kg}$
Number of moles of $\mathrm{HCI}=$ Mass of $\mathrm{HCl} /$ Molar
mass of $\mathrm{HCI}=18.25 / 36.6=0.5 \mathrm{moI}$
Molality $=$ Number of moles $/$ Mass of solvent in $\mathrm{kg}$
$
=0.5 / 0.5=1 \mathrm{~m}
$
Hence, molality of solution is $1 \mathrm{~m}$, thus correct option is (3)