(I) Potassium (II) Magnesium (III) Gold (IV) Iron

(I) KCL (II) HCL (III) CCL4 (IV) NaCL

Among the given statements, statement [C] is not true because the constitutes of compound cannot be separated by simple physical methods.

Product Z is formed by the combination of X and Y, thus having a greater mass than X and Y separately. Furthermore, Z is a completely new product, thus cannot show the same properties as X and Y.