A solution containing which one of the following pairs of substances will be a buffer solution?

a. RbCl, HCl

b. CsF, HF

c. KBr, HBr

d. NaI, HI

e. none of the above

Answer: The pairs of molecules which can form buffer solution are CSF, HF.

Explanation:

A buffer solution can only be formed by substances which are either weak acid or weak bases and mixing them with there corresponding conjugate base or conjugate acid.

Since HCl is a strong acid so the buffer solution cannot be formed using this strong acid. RbCl would provide the conjugate base anion Cl⁻ but this solution of HCl and RbCl cannot form buffer as HCl is a strong acid.

Since HF is a weak acid and hence it can form a buffer solution by mixing this weak acid with its conjugate base anion F⁻So a solution of HF and CsF would form a buffer solution. CsF would provide F⁻ ion.

HBr is also a strong acid and hence it will also not be able to form buffer solution on mixing it with its conjugate base anion Br⁻.

HI is very strong acid and hence it would not be able to form buffer solution on mixing it with its conjugate base anion I-.