Question

Select the solution that would resist a change in pH upon the addition of a small amount of acid or base.

a. A solution containing 0.10 M NaCl and 0.10 M HCl

b. A solution containing 0.05 M NH₃ and 0.10 M NH₄Cl

c. A solution containing 0.10 M HCl and 0.05 M NaOh

d. A solution containing 0.10 M NaOH and 0.75 M NaCl

Answer 1

Ans.

Buffer solutions resist the change in pH upon addition of small amount of acid or base . An acidic buffer is a solution of weak acid and salt of weak acid and strong base while a basic buffer is a solution of weak base and salt of weak base and strong acid .

From the 4 options , only (b) , solution of 0.05 M NH3 and 0.10 M NH4Cl is a buffer solution . NH3 is a weak base and NH4Cl is a salt of weak base,NH3  and strong acid,HCl . So , it is a basic buffer and answer is   option b