Question

pH value of which one of the following is NOT equal to one?

(a) 50 cm3 0.4M HCl + 50 cm3 0.2 M NaOH
(b) 0.1 M CH3COOH
(c) 0.05 MH2SO4
(d) 0.1 M HNO3​

Answer 1

Answer:

Solution :

pH=−log[H+]

(a) value of pH =0.1MHNO3=−log[0.1]=1

(b) Value of pH =0.05H2SO4=−log[2×0.05]=1

(c) Value of pH =0.1MCH3COOH≠1 as it is a weak acid so, will not undergo complete ionization.

(d) Milli-equivalent of acid =50×0.4=20

Milli-equivalent of base =50×0.2=10

Remaining acid =20−10=10 milli-eq.

[H+]=1050+50=10100=0.1

pH=−log[H+]=1