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#NaOH

14 public questions tagged with this topic.

A weak acid HY ( Ka = 2.0 × 10⁻⁵ ) is mixed with 0.01 M NaOH in a 2:1 volume ratio (acid:base). If the final [HY] = 0.04

Let volumes be 2V and V, total volume = 3V. Moles: HY = 0.04 × 3V , initial [HY] = 0.06 M , moles NaOH = 0.01V , [Y-] = (0.01V/3V) = 0.00333 M , remaining [HY] = 0.04 . pH = 4.7 + log (0.00333/0.04) = 4.7 - 1.08 = 3.62 .

Ref: NCERT Class 11 Chemistry > Chapter 6: Equilibrium > Topic: Physical Equilibrium - Solid-Liquid Gas-Liquid and Henry's Law

A weak acid HB has Ka = 4.0 × 10⁻⁶ . If its 0.05 M solution is mixed with 0.025 M NaOH , what is the pH of the resulting

HB + OH- → B- + H₂O , moles: HB = 0.05 , OH- = 0.025 , after reaction: [HB] = 0.025 M , [B-] = 0.025 M . Buffer: pH = pKa + log ([B-]/[HB]) = -log(4.0 × 10⁻⁶) + log (0.025/0.025) = 5.4 + 0 = 5.4 .

Ref: NCERT Class 11 Chemistry > Chapter 6: Equilibrium > Topic: Ionic Equilibrium - Acids Bases and pH and Ionization of Weak Acids Bases

How many grams of Na₂SO₄ are produced when 14.2 g of NaOH reacts with excess H₂SO₄? (Molar masses: NaOH = 40 g/mol, Na₂S

Reaction: 2 NaOH + H₂SO₄ → Na₂SO₄ + 2 H₂O. Moles of NaOH = 14.2 / 40 = 0.355 mol. 2 mol NaOH produce 1 mol Na₂SO₄; 0.355 mol produce 0.1775 mol. Mass = 0.1775 × 142 ≈ 25.2 g.

Ref: NCERT Class 11 Chemistry > Chapter 1: Some Basic Concepts of Chemistry > Topic: Mole Concept and Molar Masses and Percentage Composition