Question

The value for Kw is 1.0 x 10-14 at 298K, but this value is temperature dependent. Given what you know about Kw and acid/base chemistry, what will the pH of water be at 283K if the value for Kw is 0.29 x 10-14? Is this solution acidic, basic, or neutral?A. pH = 7.26, acidicB. pH = 7.26, neutralC. pH = 7.00, neutralD. pH = 14.54, basicE. pH = 7.26, basic

Answer 1

Answer:

Water is a llittle basic solution at 283K, pH = 7.26

Option E.

Explanation:

The water equilibrium is this:

2H₂O →  H₃O⁺  +  OH⁻    Kw = 1x10⁻¹⁴

At 283K, Kw = 0.29x10⁻¹⁴

[H₃O⁺] . [OH⁻] = 0.29x10⁻¹⁴

√0.29x10⁻¹⁴  = [H₃O⁺] → 5.38x10⁻⁸

√0.29x10⁻¹⁴ = [OH⁻]

- log [H₃O⁺] = pH

- log 5.38x10⁻⁸ = 7.26

pH > 7 = Basic

pH < 7 = Acidic

pH = 7 → Neutral