Question

At normal body temperature, 37°C, Kw = 2.4 × 10⁻¹⁴. Calculate the pH if [OH−] = 1.3 × 10⁻⁹ M at this temperature.

Answer 1

Using the ionization constant of water at 37°C and the hydroxide ion concentration, the pH of the solution is calculated to be approximately 5.73, which indicates that the solution is acidic.

Step-by-step explanation:

We need to calculate the pH of a solution at body temperature (37°C) where the hydroxide ion concentration ([OH−]) is 1.3 × 10⁻¹ M and the ionization constant of water (Kw) is given as 2.4 × 10⁻¹⁴. The first step is to use the given values to find the concentration of hydronium ions ([H3O+]) using the relationship Kw = [H3O+][OH−].

Kw = 2.4 × 10⁻¹⁴ M²
[OH−] = 1.3 × 10⁻¹ M
[H3O+] = Kw / [OH−] = (2.4 × 10⁻¹⁴) / (1.3 × 10⁻¹) M
[H3O+] = 1.846 × 10⁻¶ M

Next, we calculate the pH by taking the negative logarithm of the hydronium ion concentration.

pH = -log [H3O+] = −log (1.846 × 10⁻¶) ≈ 5.73

The calculated pH value is lower than the neutral pH of 7, which indicates that the solution is acidic.