Question

Calculate the pH of an aqueous solution with $0.025M{H}_{2}S{O}_4$ and $0.05MHCl$.

• A. 0.82
• B. 1.3
• C. 2.2
• D. 0.2

Answer 1

The correct option is B 1.3

Let the total volume of the solution where both mixture of $H_{2}S{O}_4$ and $HCl$ are present = $VL$.
Number of moles of $H^{+}$ coming from $H_{2}S{O}_4$ are,
$n_{H^{+}}=2\times 0.025\times V$
Number of moles of $H^{+}$ coming from $HCl$ are,
$n_{H^{+}}=0.05\times V$
Here final volume is $V_f=VL$
So, final concentration of $H^{+}$ will be:
$C_f=\frac{(2\times 0.025\times V)+(0.05\times V)}{V}=0.10MpH=-{\log }_{10}\left[0.10\right]pH=1$