The correct statement(s) about the oxoacids, $$HCl{O_4}$$ and $$HClO$$ is (are)

The color of the $${X_2}$$ molecules of group $$17$$ elements changes gradually from yellow to violet down the group. This is due to

An ideal gas is expanded from $$\left( {{p_1},{V_1},{T_1}} \right)$$ to $$\left( {{p_2},{V_2},{T_2}} \right)$$ under different conditions. The correct statement(s) among the following is (are)

Addition of excess aqueous ammonia to a pink colored aqueous solution of $$MC{l_2},6{H_2}O\left( X \right)$$ and $$N{H_4}Cl$$ gives an octahedral complex $$Y$$ in the presence of air. In aqueous solution, complex $$Y$$ behaves as $$1:3$$ electrolyte. The reaction of $$X$$ with excess $$HCl$$ at room temperature results in the formation of a blue colored complex $$Z.$$ The calculated spin only magnetic moment of $$X$$ and $$Z$$ is $$3.87$$ $$B.M.,$$ whereas it is zero for complex $$Y.$$ Among the following options, which statement(s) is (are) correct?