Question

A 0.05 molal aqueous solution boils at 373.102 K. What is the salt in question?
a. AlCl3
b. NaHSO3
c. MgCl2
d. NH4Cl
e. NaCl

I guessed NH4Cl and got 3 points off. I used the formula delta T=K boiling point X molality

Answer 1

The normal boiling point of water is 373.15K, at standard pressure. So my wondering is what pressure are you at to get that bp? Boiling points are ELEVATED when salts are added.

I wonder if your instuctor has given you the incorrect bp of water as 373K? If so, the bp elevation is .102K

.102K=X*.52*.05
X= 3.92 which points to AlCl3 as being the closest.

Take three points off for a sloppy question. Take grades with a grain of salt, in the end, they matter little.

Answer 2

I told you no cheating.