500 mL of a glucose solution contains $6.02\times {10}^{22}$ molecules. The concentration of the solution is :

No. of moles having $6.02\times {10}^{22}$ molecules $=\frac{6.02\times {10}^{22}}{6.02\times {10}^{23}}$

$=0.1 \mathrm{moles}$

Now,

$$\begin{gathered} \text{Molarity }=\frac{\text{ No. of moles }}{\mathrm{V}\text{ in }\mathrm{L}} \\ =\frac{0.1\mathrm{mol}}{0.5\mathrm{L}} \\ =0.2 \mathrm{M} \end{gathered}$$