The solubility of strontium oxide, SrO, in water is 22.8 g per 100 mL at 100 °C and 0.69 g per 100 mL at 30 °C. Is the dissolving of strontium oxide in water an endothermic or exothermic process?

Answer 1

SrO + heat ==> Sr(OH)2.
Heat makes the solubility greater (at 100 C than at zero C); therefore, the equation is as above and that is an endothermic reaction.