The indicator constant for an acidic indicator, HIn is  ${\text{5×10}}^{\text{-6}}\text{M}$. The indicator appears only in the colour of acidic form when $\left[\frac{{\text{In}}^{-}}{\text{HIn}}\right]⩽\frac{\text{1}}{\text{20}}$  and it appears only in the colour of basic form when $\left[\frac{\text{HIn}}{\text{In}}\right]⩽\frac{\text{1}}{\text{40}}$ . The pH range of indicator is [Given: log 5 = 0.7]