The concentrated sulphuric acid that is peddled commercial is 95% weight .If the density of this commercial acides 1.834 g cm^-3 the molarity of this solution is 

$$\begin{gathered} 95\mathrm{\%}{\mathrm{H}}_2{\mathrm{SO}}_4\text{ by weight means }100{\mathrm{gH}}_2{\mathrm{SO}}_4\text{ solution } \\ \text{ contains }95{\mathrm{gH}}_2{\mathrm{SO}}_4\text{ by mass. } \\ \text{ Molar mass of }{\mathrm{H}}_2{\mathrm{SO}}_4=98\mathrm{g}{\mathrm{mol}}^{-1} \\ \text{ Moles in }95\mathrm{g}=\frac{95}{98}=0.969\text{ mole } \\ \text{ Volume of }100{\mathrm{gH}}_2{\mathrm{SO}}_4 \\ =\frac{\text{ mass }}{\text{ density }}=\frac{100\mathrm{g}}{1.834\mathrm{g}{\mathrm{cm}}^{-3}} \\ =54.52{\mathrm{cm}}^3=54.52\times {10}^{-3}\mathrm{L} \\ \text{ Molarity }=\frac{\text{ Moles of solute }}{\text{ Volme of solute in }\mathrm{L}} \\ =\frac{0.969}{54.52\times {10}^{-3}}=17.8\mathrm{M} \end{gathered}$$