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Write the isomers of the compound having the formula C4H9Br. - Chemistry

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प्रश्न

Write the isomers of the compound having the formula C4H9Br.

रासायनिक समीकरण/संरचनाएँ
एक पंक्ति में उत्तर
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उत्तर

C4H9Br is a saturated compound because its parent hydrocarbon is C4H10. Its isomers are as follows –

(i) \[\ce{\underset{1-Bromobutane}{CH3 - CH2 - CH2 - CH2 - Br}}\]

(ii) \[\begin{array}{cc}
\phantom{.......}\ce{Br}\\
\phantom{.....}|\\
\ce{\underset{2-Bromobutane}{CH3-CH2-CH-CH3}}
\end{array}\]

(iii) \[\begin{array}{cc}
\ce{CH3}\phantom{....}\\
|\phantom{.......}\\
\ce{\underset{1-Bromo-2-Methylpropane}{CH3-CH-CH2Br}}
\end{array}\]

(iv) \[\begin{array}{cc}
\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - Br}\phantom{.....}\\
|\phantom{...}\\
\phantom{.}\ce{\underset{2-Bromo-2-Methylpropane}{CH3}}
\end{array}\]

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अध्याय 6: Haloalkanes and Haloarenes - Exercises [पृष्ठ १८९]

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एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
अध्याय 6 Haloalkanes and Haloarenes
Exercises | Q 6.6 | पृष्ठ १८९

संबंधित प्रश्न

What happens when chlorobenzene is subjected to hydrolysis?


What happens when ethyl chloride is treated with aqueous KOH?


C–Cl bond length in chlorobenzene is shorter than C–Cl bond length in CH3–Cl.


AgCN reacts with haloalkanes to form isocyanide. Haloalkanes react with KCN to form alkyl cyanides as the main product. Why?


Arrange the following organic compounds in descending order of their reactivity towards SN1 reaction.

C6H5CH2Br, C6H5CH(C6H5)Br, C6H5CH(CH3)Br, C6H5C(CH3)(C6H5)Br


The order of reactivity of the given haloalkanes towards nucleophile is:


Most reactive halide towards SN1 reaction is ____________.


Which of the following undergoes nucleophilic substitution exclusively by SN1 mechanism?


The correct order of increasing the reactivity of C–X bond towards nucleophile in following compounds.


    (I)


     (II)

(CH3)3CCl
    (III)

(CH3)2CHCl
    (IV)


Which reagent will you use for the following reaction?

\[\ce{CH3CH2CH2CH3 -> CH3CH2CH2CH2Cl + CH3CH2CHClCH3}\]


Cyanide ion acts as an ambident nucleophile. From which end it acts as a stronger nucleophile in aqueous medium? Give reason for your answer.


Which one of the following compounds is more reactive towards SN1 reaction?


The number of chiral alcohol (s) with molecular formula C4H10O is ______.


Give the mechanism of the following reaction:

\[\ce{CH3CH2OH ->[H2SO4][413 K] CH3CH2-O-CH2CH3 + H2O}\]


The following questions are case-based questions. Read the passage carefully and answer the questions that follow:

Nucleophilic Substitution:
Nucleophilic substitution reaction of haloalkane can be conducted according to both SN1 and SN2 mechanisms. SN1 is a two-step reaction, while SN2 is a single-step reaction. For any haloalkane, which mechanism is followed depends on factors such as the structure of haloalkane, properties of leaving group, nucleophilic reagent and solvent.

Influences of solvent polarity:
In SN1 reaction, the polarity of the system increases from the reactant to the transition state, because a polar solvent has a greater effect on the transition state than the reactant, thereby reducing activation energy and accelerating the reaction. In SN2 reaction, the polarity of the system generally does not change from the reactant to the transition state, and only charge dispersion occurs. At this time, the polar solvent has a great stabilizing effect on Nu than the transition state, thereby increasing activation energy and slow down the reaction rate. For example, the decomposition rate (SN1) of tertiary chlorobutane at 25°C in water (dielectric constant 79) is 300000 times faster than in ethanol (dielectric constant 24).

The reaction rate (SN2) of 2-bromopropane and NaOH in ethanol containing 40% water is twice slower than in absolute ethanol. Hence the level of solvent polarity has an influence on both SN1 and SN2 reactions but with different results. Generally speaking, a weak polar solvent is favourable for SN2 reaction, while a strong polar solvent is favourable for SN1. Generally speaking, the substitution reaction of tertiary haloalkane is based on SN1 mechanism in solvents with a strong polarity (for example ethanol containing water).

Answer the following questions:

(a) Why racemisation occurs in SN1? (1)

(b) Why is ethanol less polar than water? (1)

(c) Which one of, the following in each pair is more reactive towards SN2 reaction? (2)

(i) CH3 – CH2 – I or CH3CH2 – Cl

(ii)

OR

(c) Arrange the following in the increasing order of their reactivity towards SN1 reactions: (2)

(i) 2-Bromo-2-methylbutane, 1-Bromo-pentane, 2-Bromo-pentane

(ii) 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 2-Bromo-3- methylbutane


Discuss the mechanism of alkaline hydrolysis of methyl bromide.


Which alkyl halide from the following pair would you expect to react more rapidly by an SN2 mechanism? Explain your answer.

\[\begin{array}{cc}\ce{CH3CH2CHCH3}\\\phantom{...}|\\\phantom{....}\ce{Br}\end{array}\] or \[\begin{array}{cc}\phantom{.....}\ce{CH3}\\\phantom{..}|\\\ce{H3C - C - Br}\\\phantom{..}|\\\phantom{....}\ce{CH3}\end{array}\]


Which alkyl halide from the following pair would you expect to react more rapidly by an SN2 mechanism? Explain your answer.

\[\begin{array}{cc}\ce{CH3CHCH2CH2Br}\\|\phantom{.........}\\\ce{CH3}\phantom{......}\end{array}\] or \[\begin{array}{cc}\ce{CH3CH2CHCH2Br}\\\phantom{}|\\\phantom{...}\ce{CH3}\end{array}\]


Consider the reactions,

(i) \[\begin{array}{cc}
\phantom{}\ce{\underset{}{(CH3)2CH - CH2Br} ->[C2H5OH] \underset{}{(CH3)2CH - CH2OC2H5 + HBr}}\\
\end{array}\]

(ii) \[\begin{array}{cc}
\phantom{}\ce{\underset{}{(CH3)2CH - CH2Br} ->[C2H5O-] \underset{}{(CH3)2CH - CH2OC2H5 + Br-}}\\
\end{array}\]

The mechanisms of reactions (i) and (ii) are respectively:


Which of the following reactions is an example of nucleophilic substitution reaction?


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