What is the $\mathrm{pH}$ of a $2.6 \times 10^{-8} \mathrm{M~} \mathrm{H}^{+}$ion solution? $(\log 2.6=0…

What is the $\mathrm{pH}$ of a $2.6 \times 10^{-8} \mathrm{M~} \mathrm{H}^{+}$ion solution? $(\log 2.6=0.4150)$
  1. $7.6$
  2. $6.9$
  3. $10.6$
  4. $8.4$

Solution

$\mathrm{pH}=-\log \left[\mathrm{H}^{+}\right]$ As $\left(\mathrm{H}^{+}\right)$ion conc. Is less, [ $\left.\mathrm{H}^{+}\right]$obtained from $\mathrm{H}_2 \mathrm{O}$ will be considered $\left[\mathrm{H}^{+}\right]$be considered $\left[\mathrm{H}^{+}\right]$be considered $\left[\mathrm{H}^{+}\right]$be considered $\begin{aligned} & {\left[\mathrm{H}^{+}\right]=2.6 \times 10^{-8}+1 \times 10^{-7}} \\ & =1.26 \times 10^{-7}\end{aligned}$ $=1.26 \times 10^{-7}$ $\begin{aligned} & \therefore \mathrm{pH}=-\log \left[\mathrm{H}^{+}\right] \\ & =\log \left(1.26 \times 10^{-7}\right) \\ & =7-\log 1.26 \\ & =7-0.1 \\ & \mathrm{pH}=6.9\end{aligned}$

Asked in: MHT CET 2022 (05 Aug Shift 2)

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