Question

What is the $pH$ of the resulting solution when equal volumes of $0.1MNaOH$ and $0.01MHCl$ are mixed?

• A. 7
• B. 1.04
• C. 12.65
• D. 2

Answer 1

The correct option is C 12.65

When equal volumes of 0.1 M NaOH and 0.01 M HCl are mixed, the hydroxide ion concentration is
$\frac{0.1-0.01}{2}=0.045M$
The pOH of the solution is $pOH=-log\left[O{H}^{-}\right]=-log0.045=1.35$
The pH of the solution is $pH=14-pOH=14-1.35=12.65$