Question

The concentration of fluoroacetic acid (K_a of acid = 2.6 x 10^–3) which is required to get [H⁺] = 1.50 x 10^–3 M is:

(a) 0.865 M 

(b) 2.37 x 10^–3 M

(c) 2.37 x 10^–4 M 

(d) 2.37 x 10^–2 M

Answer 1

Correct option: (b) 2.37 x 10^-3 M

Explanation: 

Note: Since K_a is of the order of 10^–3 M and thus, it is not advisable to use K_a = cα². Because (1 – α) is not equal to 1 since α is not small.