Aqueous solution of which of the following shows lower `p^(H)`?

Aqucous solution of which of the following shows lower P^(H) ?

Aqucous solution of which of the following shows lower P^(H) ?

Out of NaCl and BaCl_(2) aqueous solutions, which shows more relative lowering of vapour pressure and why ?

Which of the following aqueous solutions are acidic ?

For 1 molal aqueous solution of the following compounds, which one will show the highest freezing point ?