Electrophilic Substitution

Q. Excess of isobutane on reaction with $B{r}_2$ in presence of light at ${125}^{o}C$ gives which one of the following, as the major product?

1. 

2. 

3. 

4. 

Q.

Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para halo compounds. The reaction is

(a) electrophilic elimination reaction

(b) electrophilic substitution reaction

(c) free radical addition reaction

(d) nucleophilic substitution reaction

Q. Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts. But why does the preparation of aryl iodides require the presence of an oxidizing agent?

Q.

What is the necessary condition for halogenation in benzene?

Q.

Is anisole undergoes Friedel crafts reaction?

Q. Which among $MeX,RC{H}_{2}X,R_{2}CHX\text{and}{R}_{3}CX$ is most reactive towards $S_{N}2$ reaction?

1. $MeX$
2. $RC{H}_{2}X$
3. $R_{3}CX$
4. $R_{2}CHX$

Q. What is the principal product of the following reaction?

1. 
2. 
3. 
4. 

Q. Which of the following reaction(s) is/are not representing the correct major product?

1. 
2. 
3. 
4. 

Q. Which of the following graph(s) will correspond to a $S_{N}1$ reaction mechanism?

1. 
2. 
3. 
4. 

Q. What is the order of basicity of the following compounds?

1. ${\left({CH}_3\right)}_{2}NH>{CH}_3{NH}_2>{\left({CH}_3\right)}_{3}N$
2. ${\left({CH}_3\right)}_{2}NH<{CH}_3{NH}_2<{\left({CH}_3\right)}_{3}N$
3. ${\left({CH}_3\right)}_{2}NH>{\left({CH}_3\right)}_3>{CH}_3{NH}_{2}N$
4. None of these

Q. The compound $C_7{H}_8$ undergoes the following reactions :
$C_7{H}_8\stackrel{3C{l}_2/hv}{\to }A\stackrel{B{r}_2/Fe}{\to }B\stackrel{Zn/HCl}{\to }$
The product 'C' is

(NEET - 2018 )

1. 3-bromo-2, 4, 6-trichlorotoluene
2. o-bromotoluene
3. p-bromotoluene
4. m-bromotoluene

Q. Consider the given reaction

Which of the following statement is incorrect for above reaction?

1. It is a concerted reaction
2. The reaction $S_{N}2$
3. The reaction is $S_{N}1$
4. Configuration of product is (R)

Q. Match the reactions in Column I with appropriate options in Column II.


Column 1 Column 2 @) _NaOHHO | N _@_ Racemic N1+ mixture i OH OH . ®) e / Addition HC— c c cn, S0, gc cH, reaction CH CH cH, © @_ 1. LIAIH, L{OH Substitution i reaction 2HO \ o, . e Coupling i e —2 o Carbocation © intermediate 

Q. Which of the following halogen do not form polyhalide?

1. Cl
2. F
3. Br
4. I

Q. For a particular compound, which of the following pairs can represent the empirical and the molecular formula, respectively?

1. ${CH}_2$ and $C_3{H}_9$
2. ${CH}_3$ and $C_3{H}_6$
3. $CH$ and ${CH}_4$
4. ${CH}_2$ and $C_2{H}_2$
5. $CH$ and $C_6{H}_6$

Q. What is the principal product of the following reaction?

1. 
2. 
3. 
4. 

Q. Match the species in column I with their characteristic(s) in Column II.

Q. Which of the following is Sanger's reagent?

1. 2, 4-Di-nitro iodobenzene
2. Phenyl isocyanate
3. 2, 4-Di-nitro chlorobenzene
4. 2, 4-Di-nitro flurobenzene

Q. What is the principal product of the following reaction?

1. 
2. 
3. 
4. 

Q.
Identify the reagent(s) A and condition(s) for the reaction.
A \( \rightarrow \)

Q. The oxidizing power of the halogens varies in the order

1. > < >
2. < > >
3. > > >
4. 

Q. In Rosenmund reduction, which of the following poison the catalyst Pd?

1. $BaS{O}_4$
2. S
3. Xylene
4. Quinoline

Q. Complete the given $S_{N}2$ reactions. Comment on stereochemistry.

Q. $S_{N}2$ reaction leads to:

1. inversion of configuration
2. retention of configuration
3. partial racemisation
4. no racemisation

Q. The major product of the following reaction is:

1. 
2. 
3. 
4. 

Q. For the following reaction:
$C_7{H}_{16}\underset{△\left(773K\right)}{\overset{C{r}_2{O}_3/A{l}_2{O}_3,10-20atm}{\to }}\text{Major Product}$

The major product is :

1. Heptene
2. Heptyne
3. Ethylcyclopentane
4. Toluene

Q. When pent-4-en-1-ol is treated with aqueous bromine in KOH, a cyclic bromo ether is formed rather than the expected bromohydrin. Propose a suitable mechanism for the above.

Q. Energy diagram of $S_{N}1$ and $S_{N}2$ reactions. The order of hydrolysis of RX by $S_{N}1$ is $3^o>2^o$ $1^o$ $RX$ and by ${SN}^2$ path is $1^o>2^o>3^o$ $RX$.
Which of the following statements are correct for the above energy diagras of $S_{N}1$ and $S_{N}2$ reactions?

1. $\left(I\right)$ is Fig (a) and $\left(IV\right)$ in Fig. (b) represent $S_{N}1$ reaction
2. $\left(II\right)$ is Fig (a) and $\left(III\right)$ in Fig. (b) represent $S_{N}2$ reaction
3. Fig. (a) and Fig. (b) are the energy diagrams for $1^o$ $RX$ and $3^o$ $RX$ respectively
4. Fig. (a) and Fig. (b) are the energy diagrams for $3^o$ RX and $1^o$ $RX$ respectively

Q. Which of the following catalysts is/are used for partial reduction of alkyne?

1. $Ni$
2. $N{i}_{2}B$ or P-2 catalyst
3. Lindlar catalyst
4. None of these