Question

Question 7.64 The ionization constant of chloroacetic acid is 1.35 × 10^(–3). What will be the pH of 0.1M acid and its 0.1M sodium salt solution?

Class XI Equilibrium Page 230

Answer 1

For finding PH of 0.1 M sodium salt solution use the formula ,
PH = -1/2 [ log Kw + log Ka - log Kb ]
where, Kw is the ionic product
Ka is Ionisation constant of acid
Kb is the Ionisation constant of basic.

Given, Here,
Kw = 10^-14
Ka = 1.35 × 10^-3
Kb = 0.1

now, PH = -1/2 [ log(10^-14) + log(1.35 × 10^-3) - log(0.1) ]
= -1/2 [ -14 +(-3 + 0.1303 ) -(-1)]
= -1/2 [ -14 -3 + 0.1303 +1 ]
= -1/2 [ -15.8697] = 7.93485 ≈ 7.94

hence, PH of 0.1 M acid and sodium salt solution is 7.94

Answer 2

Hi

Please see the attached file!

Hope it helps you!