Question

When $100ml$ of $N/10$ $NaOH$ are added to $50ml$ of $N/5$ $HCl$, the $pH$ of the resulting solution is:

• A. $7$
• B. greater than 7
• C. less than 7
• D. zero

Answer 1

The correct option is A $7$

Equivalents of $NaOH$ $=$ Normality of $NaOH$ $\times$ Volume of $NaOH$

$=\frac{1}{10}\times 100$

$=10$ milliequivalents.

Equivalents of $HCl$ $=$ Normality of $HCl$ $\times$ Volume of $HCl$

$=\frac{1}{5}\times 50$

$=10$ milliquivalents.

Here, equivalents of $NaOH$ $=$ equivalents of $HCl$

Therefore, the resulting solution will be neutral.

$\therefore pH$ of resulting solution is $7$.