Question

How many $H^{+}$ ions are present in 10 mL of a solution having $pH=10$?

• A. ${10}^{10}$
• B. ${10}^{-10}$
• C. $6.02\times {10}^{23}$
• D. $6.02\times {10}^{11}$

Answer 1

The correct option is D $6.02\times {10}^{11}$

$pH=10$

$Volume=10ml$

$\therefore \left[H^{+}\right]={10}^{-10}M$

No. of moles of $H^{+}$ in 10 ml is ${}^{\prime }{x}^{\prime }$.

$={10}^{-10}\times {10}^{-3}\times 10$

$={10}^{-12}$

No. of $\left[H^{+}\right]$ gms in $1$ mole = $6.023\times {10}^{23}$

Hence, no. of $H^{+}$ ion in ${10}^{-12}$moles $=6.023\times {10}^{23}\times {10}^{-12}$

$=6.023\times {10}^{11}$