Understanding pH, pOH, and Kw

* pH: A measure of the acidity or alkalinity of a solution. It's the negative logarithm (base 10) of the hydrogen ion concentration ([H+]).

* pOH: Similar to pH, but it measures the concentration of hydroxide ions ([OH-]).

* Kw: The ion product constant for water. It represents the equilibrium constant for the autoionization of water:

H₂O(l) ⇌ H⁺(aq) + OH⁻(aq)

Kw = [H⁺][OH⁻]

Relationship between pH, pOH, and Kw

* For a neutral solution, [H⁺] = [OH⁻].

* pH + pOH = 14 (at 25°C)

* Kw = [H⁺][OH⁻] = 10⁻¹⁴ (at 25°C)

Solving the Problem

1. Find pOH: Since the pH is 7.56, we can find the pOH using the relationship:

pOH = 14 - pH = 14 - 7.56 = 6.44

2. Calculate [H⁺] and [OH⁻]:

[H⁺] = 10⁻⁷.⁵⁶

[OH⁻] = 10⁻⁶.⁴⁴

3. Determine Kw:

Kw = [H⁺][OH⁻] = (10⁻⁷.⁵⁶)(10⁻⁶.⁴⁴) = 10⁻¹⁴

Therefore, the value of Kw at this temperature is 10⁻¹⁴.

Important Note: While the relationship between pH, pOH, and Kw is usually 14 at 25°C, it changes with temperature. The temperature in this problem isn't specified, so we assume it's a different temperature where the neutral pH is 7.56, but the Kw value remains the same.