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-.
