If the pH of 0.10 M monobasic acid at 298 ~K is 5.0, the value of p K_a at the same temperature is

Step-by-step solution

Given: pH for monobasic acid =5.0 The reaction for dissociation of monobasic acid is given by Since, pH =- [ H ⁺ ] [ H ⁺ ]=10⁻⁵ M Thus, x=10⁻⁵ M Now, K_a= [ H ⁺ ] [A⁻ ] [ H A] array rlrl & K_a & = [10⁻⁵ ] [10⁻⁵ ] [0.10] & & K_a & =10⁻⁹ & p K_a & =- [K_a ]=- [10⁻⁹ ] & p K_a & =9 array