ICSE Class 9 Answered

The solubility of NaNO₃ at 50^oC is 114 g i.e. 114 grams of NaNO₃ is needed to make a saturated solution of NaNO₃ in 100 g of water at 50^oC. 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 30^oC 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 30^oC is left to cool, then 43 grams of solid sodium nitrate will separate out.