Answer to Question #195096 in Chemistry for Robert

Question

What will be the pH of a solution containing 100 mol of potassium hydroxide and 0.05 mol of sulfuric acid in 100 cm3 of solution?

Answer 1

The reaction can be represented as follows:

2KOH + H₂SO₄ = K₂SO₄ + 2H₂O

From here, after the reaction, 1.00 mol - (2 × 0.05 mol) = 0.9 mol of KOH are left in the solution.

The molar concentration of KOH equals:

M(KOH) = n(KOH) / V(KOH) = 0.9 mol / 100 cm³ = 0.9 mol / 0.1 L = 9 M

From here, the pOH of the solution:

pOH = −log[OH⁻] = −log[9] = 0.95

Finally, pH equals:

pH = 14 - pOH = 14 - 0.95 = 13.05

Answer: 13.05