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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

What happens when chlorobenzene is subjected to hydrolysis? - Chemistry

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प्रश्न

What happens when chlorobenzene is subjected to hydrolysis?

रासायनिक समीकरण/संरचनाएँ
लघु उत्तरीय
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उत्तर

Chlorobenzene does not undergo hydrolysis under normal conditions. However, it undergoes hydrolysis when heated in an aqueous sodium hydroxide solution at a temperature of 623 K and a pressure of 300 atm to form phenol.

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अध्याय 6: Haloalkanes and Haloarenes - Exercises [पृष्ठ १९१]

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एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
अध्याय 6 Haloalkanes and Haloarenes
Exercises | Q 6.22 (iii) | पृष्ठ १९१

संबंधित प्रश्न

Out of , which is more reactive towards SN1 reaction and why?


Which would undergo SN2 reaction faster in the following pair and why ?


Write the structure of the major product in each of the following reaction :


In a coordination entity of the type [PtCl2(en)2]2+ which isomer will show optical isomerism?


Which of the following is a primary halide?


Which one of the following halogen compounds is difficult to be hydrolysed by SN1 mechanism?


Which of the following is the correct order of decreasing SN2 reactivity?


2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is ____________.


Among the following, the dissociation constant is highest for:


The reaction of C6H5–CH=CH–CH3 with HBr produces:


Which reagent will you use for the following reaction?

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


Write the structures and names of the compounds formed when compound ‘A’ with molecular formula, \[\ce{C7H8}\] is treated with \[\ce{Cl2}\] in the presence of \[\ce{FeCl3}\].


Chlorination of alkanes is an example of


When CH3CH2CHCl2 is treated NaNH2 product formed is:-


Arrange the following compounds in increasing order of reactivity towards SN2 reaction.

2-Bromopentane, 1-Bromopentane, 2-Bromo-2-methylbutane


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 SN2 mechanism of methyl bromide using aqueous KOH.


 Acetic anhydride from acetic acid


Which one of the following chlorohydrocarbons readily undergoes solvolysis?


HCI, Major product ______.


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