Monosubstitution of methane gives methyl chloride. It reacts at \\\\(570K\\\\) with \\\\(Si\\\\) having \\\\(Cu\\\\) as catalyst to produce \\\\((CH _{3})_{2} SiCl_{2}\\\\), which is the compound \\\\(Z\\\\). \\\\( (CH _{3})_{2} SiCl_{2}\\\\) on hydrolysis gives \\\\( (CH _{3})_{2} Si(OH)_{2}\\\\), which is a strong water repellent and quite inert chemically. Also \\\\(SiO_2\\\\) is acidic in nature.Option 'A' is correct.