Which of the following is used in the estimation of carbon monoxide?

$A$ tetravalent element forms monoxide and dioxide with oxygen. When air is passed over the heated element $(1273 \ K)$,producer gas is obtained. The monoxide of the element is a powerful reducing agent and reduces ferric oxide to iron. Identify the element and write the formulas of its monoxide and dioxide. Write chemical equations for the formation of producer gas and the reduction of ferric oxide with the monoxide.

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

The coordination number of $Al$ in the crystalline state of $AlCl_3$ is

Assertion : Silicones are hydrophobic in nature.
Reason : $Si-O-Si$ linkages are moisture sensitive.

Carbon and germanium belong to the $14^{th}$ group. The maximum coordination number of carbon is less than germanium,because of