# A solution has $pH$ = 5 is to be diluted 100 times then it will become

(a) neutral

(b) basic

(c) unaffected

(d) more acidic

$pH = 5$ means the solution is acidic. On dilution, it will remain acidic. However acidic character decreases so much that it is almost neutral ($pH = 5$ means $[H^+] = 10^{-5} M$)

After dilution, $[H^+] = \frac{10^{-5}}{100} = 10^{-7} M$
$[H^+]$ from $H_2O$ cannot be neglected.

Hence total $[H^+] = 10^{-7} + 10^{-7} = 2 \times 10^{-7}$ M
$pH = - log (2 \times 10^{-7}) = 7 = 0.3010 = 6.699 \approx 7$

Infact, in none of the given answers is correct acidic character decreases.

How u got 10^-7 + 10^-7 = 2 × 10^ -7