To calculate the solubility of the salt, we need to determine the amount of the salt dissolved in the saturated solution and then convert it to grams per decimeter cubed (g/dm³). Here’s how you can calculate it:

1. Calculate the amount of the salt dissolved in the saturated solution: Amount of salt recovered = 4 g Since the solution was initially saturated, the amount of salt dissolved in the solution before heating is equal to the amount of salt recovered. Therefore, 4 g of the salt was dissolved in the saturated solution.
2. Convert the amount of salt dissolved to grams per decimeter cubed (g/dm³): Volume of solution = 25 g (given) Solubility = Amount of salt dissolved / Volume of solution = 4 g / 25 g = 0.16 g/dm³

Therefore, the solubility of the salt is 0.16 g/dm³.