Chemistry NCERT Exemplar Solutions Class 11th Chapter Eleven

This is a Short Answers Type Questions as classified in NCERT Exemplar

H₃BO₃

Boric acid forms a hexagon and rings through hydrogen bonding and has a layer-like structure.

Boric acid is present in water as [B (OH)₄]−.H₃BO₃ electron from the OH of water and forms the complex BOH for negative for sp³ and is present in sp³ hybridisation.

Reaction:

B (OH)₃+2H₂O→ [B (OH)₄]⁻ + H₃O⁺

This is a Short Answers Type Questions as classified in NCERT Exemplar

H₃BO₃ or B (OH)₃ is an electron deficient compound or Lewis acid which easily accepts electron from OH of water and releases its proton hence it is a Monobasic acid.

Reaction:

B (OH)₃ + 2H₂O → [B (OH)₄]⁻ + H₃O⁺

This is a Long Answers Type Questions as classified in NCERT Exemplar

Boron is the only non-metallic and extremely hard element in group 13, and it is also used to make bulletproof vests. Boron exists in a variety of allotropic forms. It usually has a high melting point and no d orbital. Using 2s and 2p orbitals, it can achieve a maximum covalency of 4 . Because the octet of boron is not completed in trivalent halides of boron, it acts as Lewis acid. It forms an adduct when it reacts with Lewis base.

BF₃+NH₃→H₃N−B−F₃

This is a Long Answers Type Questions as classified in NCERT Exemplar

B₂H₆ + 2NMe₃→ 2BH₃NMe₃   BH₃NMe₃+H₂O → H₃BO₃ + NMe₃ + 6H₂

(A)                        (B)                                            (C)

(A): B₂H₆

(B): 2BH₃NMe₃

(C): H₃BO₃

This is a Long Answers Type Questions as classified in NCERT Exemplar

(i) Organosilicon polymers having (R₂SiO₂) as monomer units are called silicones. Silicones contain organic side groups which surround it giving alkane like nature and makes it hydrophobic. Silicones are applicative in electrical insulators, water proofing, sealant. They have been utilized in the biological field in cosmetic implants and other surgeries.

(ii) Boranes correspond to alkane-like compounds of boron. They consist of boron and hydrogen. Most common borane existing is dibecane.

4BF₃ + 3LiAlH₄?2B₂H₆ + 3LiF + 3AIF₃

This is a Long Answers Type Questions as classified in NCERT Exemplar

Both the compounds, BCl₃ and AlCl₃ are electron deficient compounds. In BCl₃, boron is smaller in size and cannot assemble four big chlorine atoms near it causing steric hindrance and making it unstable.

Hence, BCl₃ exists as a monomer only.

In AlCl₃, aluminum has 3p-orbitals through which chlorine atoms can be accommodated easily to complete its octet and dimer is formed.

(i)  TlCl is more stable than TlCl₃, due to inert pair effect, +1 oxile. oxidation state.

(ii) AlCl3, Al³⁺ is more stable than aluminum ions in +1 state.

(iii) Due to the inert pair effect, +1 oxidation state is more stable than the +3 oxidation state. So, InCl is more stable than InCl_3.

(iv) Boranes correspond to alkane-like compounds of boron. They consist of boron and hydrogen. Most common borane existing is dibecane.

_{4BF3 + 3LiAlH4?2B2H6 + 3LiF + 3AIF3}