The ionic product of water at ordinary temperature (25°C) is a constant value of:

Correct option is D

Explanation of the Correct Option (d): 10⁻¹⁴
· The ionic product of water ( Kw) is defined as:
· Kw = [H⁺] × [OH⁻]
· At 25°C (ordinary temperature):
· [H⁺] = 10⁻⁷ mol/L
· [OH⁻] = 10⁻⁷ mol/L
· Therefore:
· Kw = 10⁻⁷ × 10⁻⁷ = 10⁻¹⁴
· This value remains constant at a given temperature.
Explanation of Other Options
Option (a): 10⁻⁴
· Incorrect.
· Much higher than actual ionic product.
Option (b): 10⁻⁷
· Represents hydrogen or hydroxyl ion concentration, not ionic product.
Option (c): 10⁻⁸
· Incorrect numerical value for Kw.
Key Points Related to the Question
· Ionic product of water symbol: Kw
· Kw at 25°C = 10⁻¹⁴
· Basis of pH scale
· Neutral pH at 25°C = 7