Solubility is expressed as the mass of solute per 100g of solvent. It can be expressed mathematically below as:

Solubility = \(\frac{mass of solute}{mass of solvent}\) x \(\frac{100}{1}\)

= \(\frac{mass of salt}{mass of water}\) x \(\frac{100}{1}\)

Mass of salt = 2g

Mass of water = Mass of solution - mass of salt = 12.5 - 2 = 10.5g

Solubility = \(\frac{2}{10.5}\) x \(\frac{100}{1}\)

= 19.0476

= 19.05 g