At 50 °C, Kw rises to about 5.5 × 10⁻¹⁴. Which statement about pure water at 50 °C is correct?

Core Concept

Neutrality is defined by equal hydronium and hydroxide, not by the number 7. With Kw = 5.5 × 10⁻¹⁴, each ion sits near √Kw ≈ 2.3 × 10⁻⁷ M, giving pH ≈ 6.63. The water remains perfectly neutral; the neutral pH simply drifts downward as temperature rises.