Dry bleaching is done by

In the laboratory,silicon can be prepared by the reaction of:

Which of the following is/are ionic in nature?
$(i)$ $GeF_4$ $(ii)$ $SnF_4$ $(iii)$ $PbF_4$

Silicon is an important component of which of the following?

Explain the following reactions:
$(a)$ 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.

Which of the following statements is correct for the compounds $HF, HBr, H_2Se, H_2Te, H_3P$?