Delocalisation means that pairs of bonding electrons extend over three or more atoms and belong to the whole molecule. Delocalisation \(\pi \) orbital are much larger than the localized \(\pi \)  orbital and are therefore more stable.

(a) σ_{C – C}: 4; σ_C–H : 6; π_C=C :1; π C≡C:2
(b) σ_{C – C}: 3; σ_C–H: 6; π_C=C: 2.

(a) 2,2-dimethylpentane (because for the two alkyl groups on the same carbon, its locant is repeated twice)
(b) 2,4,7-trimethyloctane (because 2, 4, 7-locant set is lower than 2, 5, 7).
(c) 2-chloro-4-methylpentane (Alphabetical order of substituents)
(d) But-3-yn-1-ol (because of lower locant for the principal functional group, i.e. alcohol).

The primary suffix indicates whether the carbon chain is saturated or unsaturated while the secondary suffix indicates the functional group present in the molecule.

(a) 2, 2, 4-trimethylpentane 
Condensed formula: (CH₃)₂CHCH₂C (CH₃)₃
Bond line formula:

(b) 2-hydroxy-1, 2, 3-propanetricarboxylic acid
Condensed Formula:  (COOH)CH₂C(OH) (COOH)CH₂(COOH)
Bond line formula:

The functional groups present in the given compound are carboxylic acid (-COOH) and alcoholic (-OH) groups.
(c) Hexanedial Condensed Formula: (CHO) (CH₂)₄ (CHO)
Bond line Formula:

The functional group present in the given compound is aldehyde (-CHO).

1 M of 10 mL H₂SO₄=1M of 20 mL NH₃
1000 mL of 1M ammonia contains 14 g nitrogen 20 mL of 1M ammonia contains \(=\frac{14 \times 12}{1000} g\) nitrogen
Percentage of nitrogen \(=\frac{14 \times 20 \times 100}{1000 \times 0.5} = 56.0\%\)

(i) \({ CH }_{ 2 }={ CH }_{ 2 },CH_{ 3 }CH={ CH }_{ 2 },CH_{ 3 }{ CH }_{ 2 }CH={ CH }_{ 2 },CH_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }CH={ CH }_{ 2 }\)
(ii) \(HCOOH,{ CH }_{ 3 }COOH,{ CH }_{ 3 }{ CH }_{ 2 }COOH,{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }COOH\)
(iii) \({ CH }_{ 3 }CO{ CH }_{ 3 },{ CH }_{ 3 }{ CH }_{ 2 }CO{ CH }_{ 3 },{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }CO{ CH }_{ 3 },{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }{ CH }_{ 2 }CO{ CH }_{ 3 }\)
(iv) \({ CH }_{ 3 }OH,{ CH }_{ 3 }{ CH }_{ 2 }OH,{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }OH,{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }{ CH }_{ 2 }OH\)
(v) \(\\ HC\equiv CH,{ CH }_{ 3 }C\equiv CH,{ CH }_{ 3 }{ CH }_{ 2 }C\equiv CH,{ CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }\equiv CH\)

(i) \({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ NH }_{ 2 }\) 
(ii)
\({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }-{ CH }_{ 3 }\\ \quad \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad \quad { NH }_{ 2 }\)  
(iii)
\({ CH }_{ 3 }-{ CH }-{ CH_{ 2 } }-{ NH }_{ 2 }\\ \quad \quad \quad \quad |\\ \quad \quad \quad \quad { CH }_{ 3 }\) 
(iv)
\({ \quad \quad \quad \quad CH }_{ 3 }\\ \quad \quad \quad \quad |\\ { { CH }_{ 3 } }-{ C }-{ NH }_{ 2 }\\ \quad \quad \quad \quad |\\ \quad \quad \quad \quad { CH }_{ 3 }\) 
(v)
 \({ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ NH }-{ CH }_{ 3 }\) 
(vi)
\({ CH }_{ 3 }-{ CH }-{ NH }-{ CH }_{ 3 }\\ \quad \quad \quad \quad |\\ \quad \quad \quad \quad { CH }_{ 3 }\) 
(vii)
\({ CH }_{ 3 }-{ CH }_{ 2 }-{ NH }-{ CH }_{ 2 }-{ CH }_{ 3 }\) 
(viii)
\({ CH }_{ 3 }-{ CH }_{ 2 }-{ N }-{ CH }_{ 3 }\\ \quad \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad \quad { CH }_{ 3 }\)

Step I. Calculation of volume of unused acid
Volume of NaOH solution required = 60 cm³
Normality of NaOH solution = 1/2 N
Normality of H₂SO₄ solution = l/N
Volume of unused acid can be calculated by applying normality equation
\(\underbrace { N_{ 1 }{ V }_{ 1 } }_{ Acid } =\underbrace { { N }_{ 1 }{ V }_{ 1 } }_{ Base } \)
\(1\times V=\frac{1}{2}\times 60=30cm^3\)
Step II. Calculation of volume of acid used
Volume of acid added = 50 cm³
Volume of unused acid = 30 cm³
Volume of acid used = (50 - 30) = 20 cm³
Step III. Calculation of percentage of nitrogen
Mass of compound = 0.50 g
Volume of acid used = 20 cm³
Normality of acid used = 1N
Percentage of N =\(\frac{1.4\times Volume\ of\ acid\ used\times Normality\ of\ acid\ used}{Mass\ of\ the\ compound}\)
\(=\frac{1.4\times20\times1}{0.50}=56\%\)

Inductive Effect: The inductive effect refers to the polarity produced in a molecule as a result of higher electronegativity of one atom compared to another. Atoms or groups which lose electron towards a carbon atom are said to have + I Effect.
Those atoms or groups which draw electron away from a carbon atom are said to have -I Effect.
Common examples of -I effect are:
NO₂, F, Cl, Br, I, OH etc.
Examples of +1 effect are (Electron releasing)
(CH₃)₂C-, (CH₃)₂CH-, CH₃CH₂-, CH₃- etc.
Electromeric effect: The electromeric effect refers to the polarity produced in a multiple bonded compound as it is approached by a reagent.

The atom A has lost its share in the electron pair and B has gained this share. As a result A acquires a positive charge and B a negative charge. It is a temporary effect and takes place only in the presence of a reagent.
(a) -I-effect as shown below:
As the number of halogen atoms decreases, the overall -1- effect decreases and the acid strength decreases accordingly.

(b) +I-effect as shown below:
As the number of alkyl groups increases, the +I-effect increases and the acid strength decreases accordingly.