HF will dissociate the most/least in which of the following solutions
a) 0.1M NaF   b)0.2M NaF             c)0.1M CaF2(it is soluble)         d) 0.1 M Hcl     e) 0.1 M NaOH

It will be dissociated most in the presence of stron base as it removes all H+ ions from equilibrium and shifts it more on the right side.
HF (aq) <---> H⁺(aq) + F^- (aq)
It will be least dissociated with highest concentration of common ion H⁺ or F^-
0.2M NaF and 0.1M CaF₂