Question

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

Answer 1

Calculate molarity of solution:

Molar mass of substance x, MM$=\frac{10}{6.023\times {10}^{22}}\times (6.023\times {10}^{23})$

MM$=100g/mol$

Molarity $=\frac{{\displaystyle \frac{5}{100}}}{2}=0.025=25\times {10}^{-3}M$

Thus, the molarity of solution containing $5g$ of substance 'x' in $2L$ solution is $\mathbf{25}\times {10}^{-3}$.