How does the number of osmoles factor in when trying to calculate the molar mass of a substance?

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.

the answer is 0.42 is that is an option. this question provides no info