200   mL of 0 . 01 MHCl is mixed with 400   mL of 0 . 01 MH 2 SO 4 . The pH of the mixture is

pH of a mixture of $\mathrm{HCl}+{\mathrm{H}}_2{\mathrm{SO}}_4$ has to calculated

The number of equivalents of HCl is equal to $0.02 \mathrm{equivalents}$

The number of equivalents of ${\mathrm{H}}_2{\mathrm{SO}}_4$ given is equal to $0.008$ equivalents

Hydrogen ion concentration of the resultant mixture is equal to$\left[{\mathrm{H}}^{+}\right]=\frac{\left(0.01\times 200\right)+\left(0.01\times 2\times 400\right)}{600}$

$=\frac{2+8}{600}=\frac{10}{600}=\frac{1}{60}$

$\mathrm{pH}=-\log \left[\frac{1}{60}\right]$

$=1.78$