The pH at which Mg ( OH ) 2 [ K sp =1 × 10 -11 ] begins to precipitate from a solution containing 0.10 M Mg 2+ ions is

Chemistry · Ionic Equilibrium

JEE Main 2024 — 30 January, Shift 1 — Question 69

The pH at which $\mathrm{Mg}(\mathrm{OH})_{2}\left[\mathrm{~K}_{\mathrm{sp}}=1 \times 10^{-11}\right]$

begins to precipitate from a solution containing 0.10 M $\mathrm{Mg}^{2+}$ ions is $\qquad$

Numerical answer — enter this value.

Precipitation when $\mathrm{Q}_{\mathrm{sp}}=\mathrm{K}_{\mathrm{sp}}$

$\left[\mathrm{Mg}^{2+}\right]\left[\mathrm{OH}^{-}\right]^{2}=10^{-11}$

$0.1 \times\left[\mathrm{OH}^{-}\right]^{2}=10^{-11} \Rightarrow\left[\mathrm{OH}^{-}\right]=10^{-5}$

$\Rightarrow \mathrm{pOH}=5 \quad \Rightarrow \mathrm{pH}=9$

Answer key and solution verified before publishing.

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Exam: JEE Main 2024
Paper: 30 January, Shift 1
Subject: Chemistry
Chapter: Ionic Equilibrium
Topic: Sparingly Soluble Salts, Solubility Product & Precipitation Conditions