Question

The mole fraction of a solute in a $100\,\,molal$ aqueous solution_________.$\times 10^{-2}$ (Round off to the Nearest Integer).
[Given : Atomic masses : $H : 1.0\,u , O : 16.0 \, u]$

Answer 1

$100$ molal aqueous solution means there is $100$ mole

solute in $1\,kg =1000\,gm$ water.

Now,

mole-fraction of solute $=\frac{ n _{\text {solute }}}{ n _{\text {solute }}+ n _{\text {solvent }}}$

$=\frac{100}{100+\frac{1000}{18}}=\frac{1800}{2800}=0.6428$

$=64.28 \times 10^{-2}$