Question

Classify if any of the following solutions make a buffer. If it is a buffer, indicate what pairs of weak acid/conjugate base, or weak base/conjugate acid act as buffer (a) 0.1M HNO2 mixed with 0.1M HCl solution

(b) 0.1M HNO3 mixed with 0.1M NaNO3 solution

(c) 0.1M HNO2 mixed with 0.1M NaNO2 solution

(d) 0.1M HNO2 mixed with 0.1M NaOH solution.

Answer 1

answer : (c) 0.1M HNO2 mixed with 0.1M NaNO2 solution

explanation : weak acid and its conjugate base can act as buffer solution. in the given HNO2 is the weak acid and NO2- is the conjugate base. this pair HNO2/NO2- can act as buffer

remaining cannot act as buffer

in a ) HNO2 is acid HCl is also acid . so cannot be buffer

in b) HNO3 is strong acid . so it cannot form buffer

in d ) HNO2 is completely consumed by NaOH   . no HNO2 is left and only NaNO2 is left . so it cannot be buffer