Question

$5\, ml$ of $0.4\, N\, NaOH$ is mixed with $20\, ml$ of $0.1\, N\, HCl$. The $pH$ of the resulting solution will be

• A. 6
• B. 7
• C. 8
• D. 5

Answer 1

Answer: (B)

7

Answer 2

Milliequivalents of $NaOH = N _{1} V _{1}$
$=0.4 \times 5=0.20$

Milliequivalents of $HCl = N _{2} V _{2}$
$=0.1 \times 20=0.20$
$\because$ Milliequivalents of $NaOH$ (base)

$=$ milliequivaletns of $HCl$ (acid)

$\therefore$ Resulting solution will be neutral.

$\therefore$ Its $pH =7$