15g of methyl alcohol is present is 100ml of solution. If the density of solution is$0.96{\text{gml}}^{-1}$ , then the mass percentage of methyl alcohol in solution is     

Wt. of methyl alcohol (solute) $=15\text{ g}$

Volume of solution $\text{V}=100\text{ mL}$

Density of solution $d=0.96\text{ g}{\text{.mL}}^{-1}$

$\text{Weight}.\text{ of solution,m}=\text{V}\times d$

$m=100\text{mL}\times 0.96\text{g}{\text{.mL}}^{-\text{1}}=96g$  

                       

$\text{mass percentage}\%=\frac{\text{Wt}\text{.of solute}}{\text{Wt}\text{.of solution}}\times 100$

                       

                                   $=\frac{15}{96}\times 100=15.6$

$\therefore \text{mass percentage (w/W)\% =15}\text{.6}$