Molarity of solution = [tex] \frac{\text{weight of solute i.e. KCl (g)}}{\text{Gram Molecular Weight X Volume of solution(L)}}[/tex]
Gram molecular weight of KCl = 74.55 g
Volume of solution = 500 ml = 0.5 l
∴ Molarity = [tex] \frac{21.2}{74.55 X 0.5}[/tex] = 0.569 M