Question

Which equimolar mixture would result in a buffer with a pH less than 7?

a) HF with KF

b) HBr with KBr

c) NaOH with NaCl

d) NH3 with NH4NO3

e) HClO with HClO2

Answer 1

Acidic buffer is formed by weak acid and salt of weak acid

Basic buffer is formed by weak base and salt of weak base

for pH to be less than 77, buffer should be acidic buffer

a)

HF is weak acid and KF is conjugate base.

They form acidic buffer

b)

HBr is strong acid.

It will not form a buffer

c)

NaOH is strong base.

It will not form a buffer

d)

NH3 is weak base and NH4+ is conjugate acid.

They form basic buffer

e)

HClO is weak acid but ClO- is not present.

It will not form a buffer

Answer: a