What is the maximum amount of potassium nitrate (KNO3) that can dissolve in 100 grams of water at 40°C?

A.
25 grams

B.
50 grams

C.
62 grams

D.
75 grams

62 gram

Explanation:

Using attached solubility graph

This solubility graph tells us the amount of potassium nitrate that can be dissolved per 100g of water in order to have a saturated solution of potassium nitrate at a given temperature.

In order to find the solubility of the salt at 40∘C, start from the 40∘C mark on the graph and move up until you intersect the curve. At the point of intersection, move left until you intersect the y axis and read off the value that you land on.

In this case, you can estimate that the solubility of potassium nitrate in water at 40∘C is equal to about 62g

This tells you that a saturated solution of potassium nitrate will hold about 62 g of dissolved salt, i.e. of dissociated salt, per 100g of water at 40∘C.

Please find the attached file for the graph.