Explain the nature of the $C-X$ bond in alkyl halides.
Halogen atoms are more electronegative than carbon; therefore,the carbon-halogen bond of an alkyl halide is polarized. The carbon atom bears a partial positive charge $(\delta+)$ whereas the halogen atom bears a partial negative charge $(\delta-)$. The bond is represented as $C^{\delta+}-X^{\delta-}$.
As we go down the group in the periodic table,the size of the halogen atom increases. The fluorine atom is the smallest and the iodine atom is the largest. Consequently,the carbon-halogen bond length increases from $C-F$ to $C-I$.
Carbon-Halogen $(C-X)$ Bond Lengths,Bond Enthalpies,and Dipole Moments:
Order of dipole moment: $CH_3Cl$ > $CH_3F$ > $CH_3Br$ > $CH_3I$
Order of bond enthalpies: $CH_3F$ > $CH_3Cl$ > $CH_3Br$ > $CH_3I$
As we go down the group in the periodic table,the size of the halogen atom increases. The fluorine atom is the smallest and the iodine atom is the largest. Consequently,the carbon-halogen bond length increases from $C-F$ to $C-I$.
Carbon-Halogen $(C-X)$ Bond Lengths,Bond Enthalpies,and Dipole Moments:
| Bond | Bond length $/ pm$ | $C-X$ Bond enthalpies $/ (kJ \ mol^{-1})$ | Dipole moment $/$ Debye |
| $CH_3F$ | $139$ | $452$ | $1.847$ |
| $CH_3Cl$ | $178$ | $351$ | $1.860$ |
| $CH_3Br$ | $193$ | $293$ | $1.830$ |
| $CH_3I$ | $214$ | $234$ | $1.636$ |
Order of dipole moment: $CH_3Cl$ > $CH_3F$ > $CH_3Br$ > $CH_3I$
Order of bond enthalpies: $CH_3F$ > $CH_3Cl$ > $CH_3Br$ > $CH_3I$
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Similar Questions
Which among the following is an allylic halide?
Identify the neohexyl chloride from the following:
Given below are two statements,one is labeled as Assertion $(A)$ and the other is labeled as Reason $(R)$.
Assertion $(A)$: $CH_2=CH-CH_2-Cl$ is an example of an allyl halide.
Reason $(R)$: Allyl halides are the compounds in which the halogen atom is attached to an $sp^3$ hybridized carbon atom,which is adjacent to a carbon-carbon double bond.
In the light of the two above statements,choose the most appropriate answer from the options given below:
Assertion $(A)$: $CH_2=CH-CH_2-Cl$ is an example of an allyl halide.
Reason $(R)$: Allyl halides are the compounds in which the halogen atom is attached to an $sp^3$ hybridized carbon atom,which is adjacent to a carbon-carbon double bond.
In the light of the two above statements,choose the most appropriate answer from the options given below:
DifficultJEE MAIN 2024
View SolutionWhich of the following are vinyl chlorides?
$(a)$ $3\text{-chlorocyclohexene}$
$(b)$ $1\text{-chlorocyclohexene}$
$(c)$ $4\text{-chlorobut-1-ene}$
$(d)$ $1\text{-chloroethene}$
$(e)$ $3\text{-chlorobut-1-yne}$
$(f)$ $3\text{-chloro-2-methylpropene}$
$(a)$ $3\text{-chlorocyclohexene}$
$(b)$ $1\text{-chlorocyclohexene}$
$(c)$ $4\text{-chlorobut-1-ene}$
$(d)$ $1\text{-chloroethene}$
$(e)$ $3\text{-chlorobut-1-yne}$
$(f)$ $3\text{-chloro-2-methylpropene}$
Match the type of halide given in Column-$(I)$ with the structures in Column-$(II)$.
Column-$(I)$ (Structure) Column-$(II)$ (Type) $(A)$ $C_6H_5CH_2X$ $(i)$ $4^{\circ}$ Benzylic halide $(B)$ $C_6H_5CH(CH_3)X$ $(ii)$ $3^{\circ}$ Benzylic halide $(C)$ $C_6H_5C(CH_3)_2X$ $(iii)$ $2^{\circ}$ Benzylic halide $(D)$ $C_6H_5X$ $(iv)$ $1^{\circ}$ Benzylic halide $(v)$ Aryl halide
| Column-$(I)$ (Structure) | Column-$(II)$ (Type) |
|---|---|
| $(A)$ $C_6H_5CH_2X$ | $(i)$ $4^{\circ}$ Benzylic halide |
| $(B)$ $C_6H_5CH(CH_3)X$ | $(ii)$ $3^{\circ}$ Benzylic halide |
| $(C)$ $C_6H_5C(CH_3)_2X$ | $(iii)$ $2^{\circ}$ Benzylic halide |
| $(D)$ $C_6H_5X$ | $(iv)$ $1^{\circ}$ Benzylic halide |
| $(v)$ Aryl halide |
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