Equal weights of ethane and hydrogen are mixed in an empty container at 25$$^\circ$$C. The fraction of total pressure exerted by hydrogen is

Assuming the compounds to be completely dissociated in aqueous solution, identify the pair of the solutions that can be expected to be isotonic at the same temperature.

If p$$^\circ$$ and p are the vapour pressure of the pure solvent and solution and n₁ and n₂ are the moles of solute and solvent respectively in the solution then the correct relation between p and p$$^\circ$$ is