Question

If H+
ion concentration of a solution is increased 10 times its pH will
(1) increases by 1
(2) remains unchanged
(3) decreases by 1
(4) increases by 10

Answer 1

answer : option (3) decreased by 1

explanation : we know, $pH=-log[H^+]$

where $[H^+]$ denotes the concentration of hydrogen/hydronium ions.

now, a/c to question,

concentration of a solution is increased 10 times.

so,new concentration of hydrogen, $\bf{[H^+]}=10[H^+]$

so, new $\bf{pH=-log[H^+]}=-log10[H^+]$

or, $\bf{pH}=-log10-log[H^+]$

or, $\bf{pH}=-1+ pH$

hence, it is clear that new pH is decreased by 1

hence, option (3) correct.

Answer 2

Option C is correct.

decreases by 1 .