Question

$6.023 \times 10^{22}$ molecules are present in $10 \,g$ of a substance 'x'. The molarity of a solution containing $5\, g$ of substance 'x' in $2 \,L$ solution is _____$ \times 10^{-3}$

Answer 1

moles $=\frac{\text { number of molecules }}{6 \times 10^{23}}=\frac{\text { given mass }}{\text { molar mass }}$

$\Rightarrow $ molar mass $=\frac{10 \times 6.023 \times 10^{23}}{6.023 \times 10^{22}}=100 g / mol$

$ \Rightarrow $ molarity $=\frac{\text { moles of solute }}{\text { volume of sol }^{n}(\ell)} =\frac{(5 / 100)}{2}$

$=0.025 $