Question

In 10 ml of a solution of $pH=4$, 990 ml of 0.2 M $NaCl$ solution is added. The $pH$ of resulting solution will be:

• A. $pH=5$
• B. $pH=5.5$
• C. $pH=6$
• D. $pH=4$

Answer 1

The correct option is C $pH=6$

$NaCl$ solution dilutes the exiting solution by a 100 times as the volume changes from 10 mL to 1000 mL. Since pH follows a negative log scale, the pH increases by 2 unit from 4 to 6.