$\mathrm{pH}$ of soft drink is 3.6. Calculate the concentration of hydrogen ions in it.

$\mathrm{pH}$ of soft drink is 3.6. Calculate the concentration of hydrogen ions in it.
  1. $2.51 \times 10^{-4} \mathrm{M}$
  2. $2.3 \times 10^{-3} \mathrm{M}$
  3. $2.0 \times 10^{-3} \mathrm{M}$
  4. $2.81 \times 10^{-4} \mathrm{M}$

Solution

$\begin{aligned} & \mathrm{pH}=-\log _{10}\left[\mathrm{H}^{+}\right] \\ & {\left[\mathrm{H}^{+}\right]=10^{-\mathrm{pH}}} \\ & =10^{-3.6} \\ & =10^{-4+0.4} \quad\left(10^{0.4}=2.51\right) \\ & =10^{0.4} \times 10^{-4} \\ & {\left[\mathrm{H}^{+}\right]=2.51 \times 10^{-4} \mathrm{M}}\end{aligned}$

Asked in: MHT CET 2021 (24 Sep Shift 1)

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