Question

Consider 1.00 mole of each of the following substances:  

1) NaCl (sodium chloride)

2) CaCl₂ (calcium chloride)

3) CH₃OH (methanol)

4) Naphthalene (C₁₀H₈)

Answer the following questions:

A) Which one of the above substances would likely not change the freezing point of water at all? Explain.

B) Which one of the above substances would likely lower the freezing point of water the most? Explain.

Answer 1

A) Lowering of freezing point is directky proportional to moality of solution. If we take equal masses of different salts, the l;east molality will eb found in the salt with the highest molar mass. Here that is naphthalene and hence it is the right answer

B) to lower it by the highest margin, we need an ionic salt that posseses the largest molality. Her it will be CaCl₂. Although the molar mass of NaCl is lower,. CaCl₂ has 3 ions per molecule meaning it is the answer.