Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH 12 is . The value of is _________ (Nearest integer).
Assume complete dissociation.
Assume complete dissociation.
Show answer and solution
Answer: 05
Solution
pH = 12 → pOH = 2 → [OH⁻] = 10⁻² M
Moles of OH⁻ needed = 10⁻² × 0.1 L = 10⁻³ mol = 1 mmol
Ca(OH)₂ → Ca²⁺ + 2OH⁻, so mmol of Ca(OH)₂ = 1/2 = 0.5 mmol = 5 × 10⁻¹ mmol
Therefore x = 5.
Moles of OH⁻ needed = 10⁻² × 0.1 L = 10⁻³ mol = 1 mmol
Ca(OH)₂ → Ca²⁺ + 2OH⁻, so mmol of Ca(OH)₂ = 1/2 = 0.5 mmol = 5 × 10⁻¹ mmol
Therefore x = 5.
[JEE Main 2023 · 29 Jan · Shift 1]