Inductive effect (I):
(i) Inductive effect is defined as the change in the polarisation of a covalent bond due to the presence of adjacent bonds, atoms or groups in the molecule. This is a permanent phenomenon.
(ii) Let us explain the inductive effect by considering ethylchloride as example. The C-C bond in ethyl chloride is polar.
We know that chlorine is more electronegative than carbon, and hence it attracts the shared pair of electron between C-Cl in ethyl chloride towards itself. is develops a slight negative charge on Chlorine and a slight positive charge on carbon to which chlorine is attached.
To compensate it, the C₁ draws the shared pair of electron between itself and. C₂ . This polarisation effect is called inductive effect.
(iii) The magnitude of the charge separation decreases rapidly, as we move away from C₁ and is observed maximum for 2 carbons and almost insignicant after 4 bonds from the active group.
\(\overset { \delta }{ C } \overset { \delta + }{ { H }_{ 3 } } \longrightarrow \underset { 1 }{ C\overset { \delta + }{ { H }_{ 2 } } } \twoheadrightarrow \overset { \delta - }{ C } { l }_{ 2 }\)
It is important to note that the inductive effect does not transfer electrons from one atom to another but the displacement effect is permanent. The inductive effect represents the ability of a particular atom or a group to either withdraw or donate electron density to the attached carbon. Based on this ability the substituents are classified as +I groups and -I groups. Their ability to release or withdraw the electron through sigma covalent bond is called +I effect and -I effect respectively.
Highly electronegative atoms and atoms of groups which are carry a positive charge are electron withdrawing or -I group
Example : -F, -CI, -COOH, -NO₂, NH₂,
Higher the electronegativity of the substitutent, greater is the -I effect.
The order of the -I effect of some groups are given below :
NH³⁺ > NO₂ > CN > SO₃H > CHO > CO > COOH > COCI > CONH₂ > F > Cl > Br > I > OH > OR, NH₂ > C₆H₅ > H
Highly electropositive atoms and atoms are groups which carry a negative charge are electron donating or +I groups.
Example. Alkali metals, alkyl groups such as methyl, ethyl, negatively charged groups such as CH₃O^-, C₂H₅O^-, COO^- etc.
Lesser the electronegativity of the elements, greater is the +I effect. The relative order of +I effect of some alkyl groups is given below
\(-\mathrm{C}\left(\mathrm{CH}_3\right)_3>-\mathrm{CH}\left(\mathrm{CH}_3\right)_2>-\mathrm{CH}_2 \mathrm{CH}_3>-\mathrm{CH}_3\)
Let us understand the influence of inductive effect on some properties of organic compounds.
Reactivity :
When a highly electronegative atom such as halogen is attached to a carbon then it makes the C-X bond polar. In such cases the -I effect of halogen facilitates the attack of an incoming nucleophile at the polarised carbon, and hence increases the reactivity.

If a - I group is attached nearer to a carbonyl carbon, it decreases the availability of electron density-on the carbonyl carbon, and hence increases the rate of the nucelophilic addition reaction.
Aciditv of carborvlic acids :
When a halogen atom is attached to the carbon which is nearer to the carboxylic acid group, its -I effect withdraws the bonded electrons towards itself and makes the ionisation of H⁺ easy. The acidity of various chloro acetic acid is in the following order. The strength of the acid increases with increase in the -I effect of the group attached to the carboxyl group.
Tiichloro acetic acid > Dichloro acetic acid > Chloro acetic acid > acetic acid

(w) = 0.33 g
y = 0.397 g
\(\% \mathrm{P}=\frac{62}{222} \times \frac{\mathrm{y}}{\mathrm{w}} \times 100=\frac{62}{222} \times \frac{0.397}{0.33} \times 100=33.60 \%\)

Molecular orbital diagram of nitrogen molecule (N₂) :
Electronic configuration of N atom 1s² 2s² 2p³
Electronic configuration of N, molecule
\(\sigma^{2}_{1s},\sigma^{*2}_{1s},\sigma^{2}_{2s},\sigma^{*2}_{2s}\)\(\pi^{2}_{2py},\pi^{2}_{2pz},\sigma^2_{2px}\)
Bond order = \({N_b-N_a\over2}={10-4\over2}=3\)
Molecule has no unpaired electrons hence it is diamagnetic.

\(\overset { \underset { | }{ Cl } }{ \underset { \overset { | }{ Cl } }{ CH } } -{ CH }_{ 3 }\quad (A)\) 1, 1,-dichloro ethane
\(\underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } -\underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } \) (B) 1, 2, dichloro ethane
\(\overset { \underset { | }{ Cl } }{ \underset { \overset { | }{ Cl } }{ CH } } -{ CH }_{ 3 }\underset { aq\quad KOH }{ \longrightarrow } \left[ \overset { \underset { | }{ OH } }{ \underset { \overset { | }{ OH } }{ CH } } -{ CH }_{ 3 } \right] \underset { -{ H }_{ 2 }) }{ \longrightarrow } { CH }_{ 3 }CHO\)
(A)                                                                    (C)
1, 1, dichloro ethane                                      Acetaldhyde
\(A \ \ \overset { \underset { | }{ Cl } }{ \underset { \overset { | }{ Cl } }{ CH } } -{ CH }_{ 3 }\)  -1,1 dichloro ethane
B  \(\underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } -\underset { \overset { | }{ Cl } }{ { CH }_{ 2 } } \)-1, 2 dichloro ethane
C CH₃CHO -Acetaldehyde 
D \(\underset { \overset { | }{ OH } }{ { CH }_{ 2 } } -\underset { \overset { | }{ OH } }{ { CH }_{ 2 } } \)-Ethyleneglycol

a) Electrophiles:
Electrophiles are reagents that are attracted towards negative charge or electron rich center. They are either positively charged ions or electron deficient neutral molecules. All Lewis acids act as electrophiles.
Neutral molecules like SnCl₄ can also act as an electrophile, as it has vacant d-orbitals which can accommodate the electrons from others.

b) Nucleophiles:
Nucleophiles are reagents that has high affinity for electro positive centers. They possess an atom has an unshared pair of electrons, and hence it is in search for an electro positive centre where it can have an opportunity to share its elections to form a covalent bond, and gets stabilised.
They are usually negatively charged ions or electron rich neutral molecules (contains one or more lone pair of electrons). AII Lewis bases act as nucleophiles.

The first six members of nitro alkanes are
(i) CH₂-NO₂ - Nitromethane
(ii) CH₂-CH₂-NO₂ - Nitroethane
(iii) CH₃-CH₂-CH₂-NO₂ - 1- nitropropane'
(iv) CH₃-CH₂-CH₂-CH₂-NO₂ - 1- nitrobutane
(v) CH₃-CH₂-CH₂-CH₂-CH₂-NO₂ - 1- nitropentane
(vi) CH₂-CH₂-CH₂-CH₂-CH₂-CH₂ - NO₂ - 1- nitrohexane

Weight of an organic compound = 0.24 g
Weight of Mg₂P₂O₇ = 0.66 g = y
\( \% \mathrm{P} =\frac{62}{222} \times \frac{\mathrm{y}}{\mathrm{w}} \times 100 \)
\(=\frac{62}{222} \times \frac{0.66}{0.24} \times 100=76.80 \%\)

(w) = 0.33 g
(c) = 0.397 g
\(\% I=\frac{127}{235} \times \frac{c}{w} \times 100=\frac{127}{235} \times \frac{0.235}{0.40} \times 100=31.75 \%\)

(w) = 0.185 g
(x) = 0.320 g
\(\% \mathrm{Br}=\frac{80}{188} \times \frac{b}{w} \times 100=\frac{80}{188} \times \frac{0.320}{0.185} \times 100=73.6 \%\)

Molecules having polar bonds will not necessarily have a dipole moment. For example, the linear form of carbon dioxide has zero dipole moment, even though it has two polar bonds. In CO₂, tlie dipole moments of two polar bonds (CO) are equal in magnitude but have opposite direction. Hence, the net dipole moment of the CO₂ is,
\(\mu=\mu_{1}+\mu_{2}=\mu_{1}+(-\mu_{1})=0.\)


In this case \(\mu=\overrightarrow { { \mu }_{ 1 } } +\overrightarrow { { \mu }_{ 2 } } \quad \)
\(=\overrightarrow { { \mu }_{ 1 } } +\overrightarrow { ({ \mu }_{ 1 }) } =0\)

Dipole moment :
The polarity of a covalent bond can be measured in terms of dipole moment which is defined as \(\mu=q \times 2d\)
Where \(\mu\) is the dipole moment, q is the charge and 2d is the distance between the two charges.
Where p is the dipole moment, q is the charge and 2d is the distance between the two charges. The dipole moment is a vector and the direction of the dipole moment vector points from the negative charge to positive charge.

The unit for dipole moment is columb meter (C m). It is usually expressed in Debye unit (D). The conversion factor is 1 Debye = 3.336 x 10^-30 C m.

(i)\({ CH }_{ 3 }-\overset { \overset { { CH }_{ 3 } }{ | } }{ { CH }-\underset { \overset { | }{ { CH }_{ 3 } } }{ CH } - } CH_{ 2 }-{ CH }_{ 2 }-\overset { \overset { { CH }_{ 2 }-\overset { \underset { | }{ { CH }_{ 3 } } }{ CH } -{ CH }_{ 3 } }{ | } }{ CH- } { CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 3 }\)
(ii) 

(iii) \({ CH }_{ 3 }-\underset { \underset { { CH }_{ 3 } }{ | } }{ CH } -{ CH }_{ 2 }-{ CH }_{ 2 }-\underset { \overset { | }{ \overset { CH-CH_{ 3 } }{ \overset { | }{ { H }_{ 3 }C-CH-{ CH }_{ 3 } } } } }{ CH } -{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 2 }-{ CH }_{ 3 }\)

Aliphatic monohydric alcohol : R - OH