A sample X of $$\text{MCl}_2$$ was found to contain a small quantity of $$\text{M(OH)}_2$$ as an impurity, both of the compounds being soluble in water. In an experiment 30 g of the above sample X was dissolved in 60 mL of 0.4 M HCl to give solution Y, and 20 mL of 0.4 M NaOH was required to neutralise the excess HCl in solution Y. The percentage of $$\text{M(OH)}_2$$ in sample X, given that the molar mass of $$\text{M(OH)}_2$$ is 65 g per mol, is