Question

what weight of sodium nitrate will seperate when a saturated solution containing 50 gram of water is cooled from 50°c to 30°c?the solublity of NaNo₃ at 50°c and 30° is 114g and 86g respectively.

Answer 1

The solubility of NaNO3 at 50oC is 114 g i.e. 114 grams of NaNO3 is needed to make a saturated solution of NaNO3 in 100 g of water at 50oC. Hence, to make a saturated solution in 50 grams of water, we will require half of 114 grams of NaNO3 i.e. = 114/2 = 57 grams of NaNO3.

Hence, when a saturated solution of sodium nitrate at 50oC is left to cool, then 57 grams of solid sodium nitrate will separate out.

Similarly, solubility of NaNO3 at 30oC is 86 g hence, to make a saturated solution in 50 grams of water, we will require half of 86 g of NaNO3 i.e. = 86/2 = 43 grams of NaNO3.

Hence, when a saturated solution of sodium nitrate at 30oC is left to cool, then 43 grams of solid sodium nitrate will separate out.