Dear Kajal
I know that the lower pKa is a stronger acid, which makes answer HB.
Hence HB is stronger acid.
What secind part really asks if it this reaction will happen:
HB + A- = B- + HA
and to find the answer you have to know which conjugate base - A- or B- is stronger.
HB + A- = B- + HA strong acid + A- = B- + weak acid Since HB is a stronger acid, isn't A- a stronger base? stronger acid=weaker conj. base?
Hence answer will be yes.
Regards
Arun (askIITians forum expert)