(i) In triphenylmethyl cation, due to resonance the positive charge can move at both the o- and p-positions of each benzene ring.

[Six more structures are possible due to resonance in other two benzene rings]
(ii) Totally nine resonance structures are possible for 3 benzene rings
(iii) ∴ Triphenylmethyl cation is highly stable due to these nine resonance structure.

(i) 2-methyl butane has four different sets of equivalent H-atoms.
(ii) Removal of H-atom from any of C-atom gives four different carbocations.
(i) \(C{ H }_{ 3 }\rightarrow \overset { \beta }{ \underset { \overset { | }{ C{ H }_{ 3 } } }{ CH } } \rightarrow \overset { \alpha }{ C{ H }_{ 2 } } \rightarrow \overset { + }{ C{ H }_{ 2 } } \)
(ii) \(C{ H }_{ 3 }\rightarrow \underset { \overset { | }{ C{ H }_{ 3 } } }{ CH } -\overset { + }{ C{ H } } \leftarrow C{ H }_{ 3 }\)
(iii) \(C{ H }_{ 3 }\rightarrow \overset { + }{ \underset { \overset { | }{ C{ H }_{ 3 } } }{ C } } \leftarrow C{ H }_{ 2 }-C{ H }_{ 3 }\)
(iv) \(\overset { + }{ C{ H }_{ 2 } } \leftarrow \underset { \overset { | }{ C{ H }_{ 3 } } }{ CH } \leftarrow C{ H }_{ 2 }-C{ H }_{ 3 }\)
(iii) Stability order of carbocation is 3⁰ > 2⁰ > 1⁰
(iv) Though I & IV are primary carbocations, I has (α-CH₃ group at β-carbon and while IV has -CH₃ at α-carbon.
(v) +I effect decreases with distance, hence IV is more stable than I
(vi) ∴ The overall stability is I < IV < II < III

(i) C-Br is more polar than C-H (due to electronegativity )
(ii) C-O is more polar than C-N
(iii) C-O is more polar than C-S

(i) CH₃ - OH : Does not exist as resonance hybrid due to absence of π-electrons.
(ii) R-CO NH₂ : Can exist as resonance hybrid due to the presence of non-bonding electrons on N and n-electrons on C = O bond.

(iii) CH₃-CH = CH-CH₂NH₂: Does not exist as resonance hybrid, because the lone pair on N-atom is not conjugated with n-electrons of the double bond

(i) Brominatin of alkene to give bromo alkane.

(iii) In this reaction, benzoyl peroxide acts as a radical initiator. The mechanism involves free radicals.
\({ H }_{ 2 }C=CH+H-Br\overset { \overset { Benzoyl }{ Peroxide } }{ \longrightarrow } C{ H }_{ 3 }-C{ H }_{ 2 }-Br\)