Question

How many grams of salt can be dissolved in $100g$ of ${H_2}O$ at $80$ degree Celsius?

Answer 1

The ability of a substance to get dissolved in a solvent is called solubility. The substance which is dissolved is called solute and the substance in which the solute is dissolved is called solvent.

Complete step by step answer:
We need to calculate the grams of salt that can be dissolved in $100g$ of ${H_2}O$ at $80$ degree Celsius. Given that solvent is water. Let us take sodium chloride (NaCl), commonly known as table salt as the solute. Now we need to determine the weight of NaCl that can be dissolved in $100g$ of ${H_2}O$ at $80$ degree Celsius.
Solubility of a substance in a solvent increases with temperature. Solubility of NaCl in water at room temperature is approximately $35g/100g$ water. The temperature given in the question is $80{}^0C$ . As solubility increases with temperature, more NaCl can be dissolved in $100g$ of water at $80{}^0C$. For NaCl, increase in solubility with temperature is much less compared to other salts like $NaN{O_3}$ , $CaC{l_2}$ , KCl etc. Hence approximately $40g$ NaCl can be dissolved in $100g$ of water at $80{}^0C$ .
We can get an unsaturated solution of sodium chloride if we dissolve less than $40g$ of NaCl in $100g$ of water at $80{}^0C$ . A saturated solution of sodium chloride can be obtained by dissolving approximately $40g$ of NaCl in $100g$ of water at $80{}^0C$ .

Note:
In a saturated solution, the maximum amount of solute is dissolved in the solvent. This is an equilibrium condition. A solution which contains more than the maximum amount of solute that can be dissolved is called supersaturated solution. A supersaturated solution can be crystallised easily.