Question

$100$ ml of $0.15$ M $HCl$ is mixed with $100$ ml of $0.005$ M $HCl$, what is the $pH$ of the resulting solution approximately:

• A. $2.5$
• B. $1.1$
• C. $2$
• D. $1$

Answer 1

The correct option is B $1.1$

The total concentration of the solution will be,

$\left[H^{+}\right]=\frac{100\times 0.15+100\times 0.005}{100+100}=0.0775$

$pH=-log\left[H^{+}\right]=-log\left(0.0775\right)=1.1$.

Option B is correct.