Calculate the amount of solute excess out when the 60 gm of saturated solution of NH4Cl having solubility of 57 at 60 ℃ is cooled to 20 ℃ , the solubility being 35.

weight of salt = 90 gram,

solubility = 50

sing formula

solubility of solute =

×100

or 50=

90gm

×100

so weight of solvent in saturated solution =

50

90gm

×100=180gm

Hence 180 gm of water is required to prepare a saturated solution.

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