Answer: The mass of the sample will be 1417.7 grams.
Explanation:
We are given:

This means that 1 mole of NaCl has an enthalpy of fusion of 30.2 kJ
1 mole of NaCl has a mass of 58.44 grams.
So, 30.2 kJ of heat is require for a mass 58.44 grams of NaCl
So, 732.6 kJ of heat will be required for =
= 1417.65 grams of NaCl.
Hence, the mass of NaCl sample will be 1417.7 grams.
It is B nevermind I thought it was c but it wasn't.
Answer : The change in boiling point is, 
Explanation :
Formula used :

where,
= change in boiling point = ?
i = Van't Hoff factor = 3 (for MgI₂ electrolyte)
= boiling point constant for water = 
m = molality = 0.615 m
Now put all the given values in this formula, we get


Therefore, the change in boiling point is, 