The mole fraction of NaCl is .015 in Benzene. What is the mass% of NaCl and what is the new boiling point of the solution?

What is conserved in the reaction shown below? h2(g) + cl2 (g) --> 2hcl(g)a. mass onlyb. mass and moles onlyc. mass, moles, and molecules onlyd. mass, moles, molecules, and volume