Question

Given that Kw for water is 2.4×10−14 M2 at 37 °C, calculate the pH of a neutral aqueous solution at 37 °C, which is the normal human body temperature. pH= Is a pH=7.00 solution acidic, basic, or neutral at 37 °C? neutral basic acidic

Answer 1

Answer:

pH = 6.80. The aqueous solution is slightly acid

If pH is 7.00 at 37°C, solution is neutral

Explanation:

2H₂O ⇄  H₃O⁺  + OH⁻     Kw = 2.4×10⁻¹⁴

To determine the pH of a solution, we must consider the [H₃O⁺]

[H₃O⁺] . [OH⁻] = 2.4×10⁻¹⁴

[H₃O⁺] =  [OH⁻]  → √2.4×10⁻¹⁴ =  [H₃O⁺]

1.55×10⁻⁷ = [H₃O⁺]

pH = - log 1.55×10⁻⁷ = 6.80

pH = 7 → neutral

pH < 7 → acid

pH > 7→ basic