Nucleophilic Substitution in Aryl Halides

Q.

Which of the following compounds will show retention in the configuration on nucleophilic substitution by ${\mathrm{OH}}^{-}$ ion?

1. 

2. 

3. 

4. 

Q.

What are interfering radicals?

Q.

When chlorobenzene is treated with NaNH₂ in liquid ammonia at 196K, aniline is formed. This reaction takes place by

1. E1cB mechanism

2. Benzyne mechanism

3. E2 mechanism

4. E1 mechanism

Q. Predict the product of the following reactions:

$A$:

$B$:

$C$:

$D$:

Q.

When chlorobenzene is treated with NaNH₂ in liquid ammonia at 196K, aniline is formed. This reaction takes place by

1. E1 mechanism

2. E2 mechanism

3. E1cB mechanism

4. Benzyne mechanism

Q.

Assertion: Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution.

Reason: Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring

1. Assertion and reason both are correct statements but reason is not correct explanation of assertion.
2. Assertion and reason both are wrong statements.
3. Assertion and reason both are correct and reason is the correct explanation of assertion.
4. Assertion is wrong but reason is correct statement.
5. Assertion is correct but reason is wrong statement.

Q. The correct decreasing order of dehydration of following alcohols with concentrated $H_{2}S{O}_4$ is:

1. C > D > A > b
2. D > A > C > B
3. A > B > C > D
4. D > C > A > B

Q.
Major product of the given reaction is:

1. 
2. 
3. 
4. 

Q. 39.The reaction of the benzyl chloride with sodium cyanide followed by reduction with hydrogen in the presence of nickel gives beta-phenyl ethylamine N-isobutylaniline. Benzyl amine. Aniline

Q. The correct order of nucleophilic substitution in 1) Chlorobenzene 2) Ortho nitro chloro Benzene 3) 1-3 dinitro chloro Benzene 4) 1-3-5 trinitrochlorobenzene

Q.

Write the mechanism of the following reaction:

Q. The structure of the major product formed in the following reaction is

1. 
2. 
3. 
4. 

Q. Out of , which is an example of vinylic halide?

Q. How does iodoform reaction with sodium hypoiodite is used for detection of CH3CH(OH) group?

Q.

Nitric oxide reacts with Br₂ and gives nitrosyl bromide as per reaction given below:

When 0.087 mol of NO and 0.0437 mol of Br₂ are mixed in a closed container at constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate equilibrium amount of NO and Br₂.

Q.

Give the reason for bleaching action of Cl₂.

Q.

When magnesium burns in oxygen a white powder MgO is formed. Write the balanced chemical equation.

Q. In a zero order reaction 20%of the reaction complete in 10s .how much time it will take to complete 50%of the reaction?

Q. Aryl halides are less reactive than alkyl halides towards nucleophilic substitution reaction because of

1. formation of less stable carbonium ion
2. inductive effect
3. larger C—halogen bond
4. resonance stabilization

Q. Isopropyl alcohol on oxidation forms

1. Acetone
2. Ether
3. Ethylene
4. Acetaldehyde

Q.

In the question arrange the compounds in increasing order of rate of reaction towards nucleophilic substitution.

(a) (iii) < (ii) < (i) (b) (ii) < (iii) < (i)

(c) (i) < (iii) < (ii) (d) (i) < (ii) < (iii)

Q. Reaction of aniline with Benzaldehyde produces :

1. unsaturated acid
2. azoxybenzene
3. Benzoin
4. Schiff’s base

Q.

Which alkyl halide from the following pairs would you expect to react more rapidly by an S_N2 mechanism and why?

$C{H}_{3}C{H}_2-C{H}_2-Br$ & $C{H}_{3}C{H}_2-CH\left(Br\right)-C{H}_3$

Q. Acetic acid forms a dimer in non polar solvent benzene through hydrogen bonding the observed molecular mass of acetic acid assuming $25\%$ dimerisation in benzene is $x$. The value of $0.875x$ is

Q. In Dow's process, the starting raw material is:

1. phenol
2. chlorobenzene
3. aniline
4. diazobenzene

Q. Bottles containing C₆H₅I and C₆H₅CH₂I lost their original labels. They are labelled as A and B. A and B were separately taken in a test tubes and boiled with NaOHsolution.Then in each test tube Dilute HNO₃ and Ag NO₃ was added. Substance B gave a yellow precipitate. Which one of thefollowingstatements is true for this experiment?

1. Addition of HNO₃ was not necessary

2. B was C₆H₅I

3. A was C₆H₅Cl

4. A was C₆H₅CH₂I

Q. Predict the end product in following reaction scheme:

Compound (B) is:

1. 
2. 
3. 
4. 

Q. Action of alcoholic $AgN{O}_3$ on chlorobenezene is similar to the action on

1. Ally chloride
2. Vinyl chloride
3. Isopropyl chloride
4. Benzyl chloride

Q. A compound (X) has a molecular formula $C_{2}C{l}_{3}OH$. It reduces Fehling's solution and on oxidation gives a monocarboxylic acid (Y). It can be obtained by the action of chlorine on ethanol. (X) is:

1. Methyl chloride
2. Monochloroacetic acid
3. Chloral
4. Chloroform

Q. Why are aryl halides less reactive towards nucleophilic substitution reactions than alkyl halides? How can we enhance the reactivity of aryl halides?