NCERT Solutions for Chapter: The p-Block Elements, Exercise 1: Long Answer Type

Identify that compound in the following pair which has group $13$ element in more stable oxidation state. Give reason for your choice. State the nature of bonding also.

${\mathrm{InCl}}_3, \mathrm{InCl}$

${\mathrm{BCl}}_3$ exists as monomer whereas ${\mathrm{AlCl}}_3$ is dimerised through halogen bridging.Give reason. Explain the structure of the dimer of ${\mathrm{AlCl}}_3$ also.

Boron fluoride exists as ${\mathrm{BF}}_3$ but boron hydride doesn’t exist as ${\mathrm{BH}}_3$. Give reason. In which form does it exist? Explain its structure.

What are silicones? State the uses of silicones.

What are boranes? Give chemical equation for the preparation of diborane.

A compound $\left(\mathrm{A}\right)$ of boron reacts with ${\mathrm{NMe}}_3$ to give an adduct $\left(\mathrm{B}\right)$ which on hydrolysis gives a compound $\left(\mathrm{C}\right)$ and hydrogen gas. Compound $\left(\mathrm{C}\right)$ is an acid. Identify the compounds $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$. Give the reactions involved.

A nonmetallic element of group $13$, used in making bulletproof vests is extremely hard solid of black colour. It can exist in many allotropic forms and has unusually high melting point. Its trifluoride acts as Lewis acid towards ammonia. The element exhibits maximum covalency of four. Identify the element and write the reaction of its trifluoride with ammonia. Explain why does the trifluoride act as a Lewis acid.

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