Introduction to Electrophilic Substitution

Q.

Is ${\mathrm{OCH}}_3$ an electron-withdrawing group?

Q.

How Do You Know Which Group Is Activating And Deactivating?

Q. The correct order of increasing reactivity C- X bond towards nucleophile in the following in the following compounds is:

\( \left( CH _{3}\right)_{3} C - X \) \( \left( CH _{3}\right)_{2} CH - X \) (I) (II) (III) (IV)

Q.

What is the formula for chlorine water?

Q. Wurtz reaction fails in case of tert-alkyl halides. Why?

Q.

Why is Chlorine an electrophile?

Q. Decreasing order of reactivity of HX in the reaction $ROH+HX\to RX+H_{2}O$

1. $HI>HBr>HCl>HF$
2. $HBr>HCl>Hl>HF$
3. $HCl>HBr>Hl>HF$
4. $HF>HBr>HCl>HI$

Q.

WHAT IS ADDITION REACTION AND SUBSTITUTION REACTION

Q. 16 The number of primary alcohols possible with the formula C4H10O is- A) 2 B) 3 C) 4 D) 5

Q. Sodium stearate $C{H}_3(C{H}_2{)}_{16}CO{O}^{–}N{a}^{+}$ is an anionic surfactant which forms micelles in oil. Choose the correct statement for it from the following :

1. It forms non–spherical micelles with $C{H}_3(C{H}_2{)}_{16}-$group pointing towards the centre.
2. It forms spherical micelles with $C{H}_3(C{H}_2{)}_{16}-$ group pointing outwards on the surface of sphere
3. It forms non–spherical micelles with $–COO–$ group pointing outwards on the surface
4. It forms spherical micelles with $C{H}_3(C{H}_2{)}_{16}-$ group pointing towards the centre of sphere.

Q. Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Treatment of chloroethane with a saturated solution of $AgCN$ gives ethyl isocyanide as a major product.
Reason (R): Cyanide ion $\left(C{N}^{-}\right)$ is an ambident nucleophile.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true

Q. In certain reaction, 10% of the reactant decomposes in one hour, 20% in two hours, 30% in three hours and so on. The dimensions of the rate constant is

1. $hou{r}^{-}{}^1$
2. $mol{L}^{-}{}^1{s}^{-}{}^1$
3. $Lmo{l}^{-1}{s}^{-1}$
4. $mol{s}^{-}{}^1$

Q. The most reactive compound towards the formation of cyanohydrin on treatment with $KCN$ followed by acidification is

1. Benzaldehyde
2. P-Nitrobenzaldehyde
3. Phenyl Acetaldehyde
4. P-Hydroxybenzaldehyde

Q.

If the rate of reaction increases 27 times , when temperature is increased by 30K, then temperature coefficient of the reaction is

Q.

The degeneracy of d orbital is removed with the approach of the ligand due to

1. Ligand nucleus-metal electron attractions

2. Ligand electron-metal nucleus attractions

3. Ligand electron-metal electron repulsions

4. Ligand nucleus-metal nucleus repulsions

Q.

Describe how the enthalpy of a reaction remains unchanged when a catalyst is used in the reaction.

Q.

For a reaction A → B, it is found that the rate of the reaction quadruples when the concentration of A is doubled. The rate for the reaction is Rate = k [A]^x, where the value of x is:

1. 2

2. 3

3. 0

4. 1

Q.

What does a key dimension mean?

Q. Although chlorine is an electron withdrawing group, yet it is ortho-para directing in electrophilic aromatic substitution reactions. Why?

Q. What is difference between atomic hybrid orbital & molecular orbital ??

Q. Predict the products of the given reaction.
$C{H}_3-O-CH(C{H}_3{)}_2+HI\stackrel{\text{Heated}}{\to }$

1. $IC{H}_{2}OCH(C{H}_3{)}_2$
2. 
3. $C{H}_{3}I+(C{H}_3{)}_{2}CHOH$
4. $C{H}_{3}OH+(C{H}_3{)}_{2}CHI$

Q.

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Q. The most deactivating group for electrophilic substitution reaction in benzene ring is

1. $-C{F}_3$
2. $-N{O}_2$
3. $-OC{H}_3$
4. $-CHO$

Q. How does the presence of an electron withdrawing group or an electron releasing group effect the ease of dehydration of an alcohol?

Q. As the initial concentration increases from $0.75$ to $1.55M$ in a reaction, $t_{1/2}$ decreases from $60$ to $29s$. The order of the reaction is:

1. Zero
2. First
3. Second
4. Third

Q.

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Q. The correct order of following compounds for increasing reactivity towards electrophilic substitution is:

1. IV< II < I < III
2. III < II < I < IV
3. I < IV < III < II
4. II < III < I < IV

Q.

Electrophilic substitution reactions are faster in

1. Chlorobenzene

2. Phenol

3. Anisole

4. Phenetole

Q. The increasing order of the reactivity of the following compounds towards electrophilic aromatic substitution reaction is:

1. $I<III<II$
2. $III<II<I$
3. $II<I<III$
4. $III<I<II$

Q. The temperature coefficient of a certain reaction is found to be 3. if temperature changes from 25^° to 55^° the new rate of reaction will be: a. 8 times b. 9times c. 16times d. 27times