Explain the following reaction: a. Silicon is heated with methyl chloride at high temperature in the presence of copper. b. Silicon dioxide is treated with hydrogen fluoride. c. CO is heated with ZnO. d. Hydrated alumina is treated with aqueous NaOH solution.

Explain the following reaction: a. Silicon is heated with methyl chlo

1.	Explain the following reaction: a. Silicon is heated with methyl chloride at high temperature in the presence of copper. b. Silicon dioxide is treated with hydrogen fluoride. c. CO is heated with ZnO. d. Hydrated alumina is treated with aqueous NaOH solution.
Answer» Solution :a. A mixture of mono-and di-acid trimethylchloro silanes alongwith a small amount of tetramethyl silance is formed. `Si+CH_(3)Clunderset("373 K")overset("Cu powder")to CH_(3)SiCl_(3)+(CH_(3))_(2)SiCl_(2)+(CH_(3))_(3)SiCl+(CH_(3))_(4)Si` b. `SiO_(2)`, reacts with `HF` on heating to form silicon TETRAFLUORIDE which DISSOLVES in HF to form hydroflourosilicic acid. `SiO_(2)+4HFto underset("tetrafluoride")underset("Silicon")(SiF_(4))+H_(2)O` `SiF_(4)+2HFto underset("(SOLUBLE)")underset("Hydrofluorosilicic acid")(H_(2)SiF_(6))` c.`CO+ZnOoverset(Delta)toZn+CO_(2)uarr` d. Hydrated alumina dissolves in aqueous `NaOH` solution to form sodium meta-aluminate. `underset("or bauxite")underset("alumina")underset("Hydrated")(Al_(2)O_(3).2H_(2)O_((s)))+NaOH_((aq))overset(Delta)tounderset("(soluble)")underset("meta-aluminate")underset("Sodium")(2NaAlO_(2))+3H_(2)O or Al_(2)O_(3).2H_(2)O_((s))+2NaOH_((aq))+H_(2)O_((l))overset(Delta)tounderset("Sodium tetrahydro-aluminate(III)")(2Na[Al(OH)_(4)]_((aq)))`