Alkenes - geometrical isomerism and electrophilic addition — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Geometrical isomerism in alkenes arises because rotation about the carbon-carbon double bond is

• A. restricted
• B. completely free
• C. faster than rotation about a single bond
• D. irrelevant to substituent arrangement

Question 2 · difficulty L2 · understanding

IUPAC name of the some alkenes are given below. Find out the correct stability order. A. 2-Methylbut-2-ene B. cis-But-2-ene C. 2,3-Dimethylbut-2-ene D. Prop-1-ene Choose the correct answer from the options given below :

• A. $\mathrm{C}>\mathrm{A}>\mathrm{B}>\mathrm{D}$
• B. $\mathrm{C}>\mathrm{A}>\mathrm{D}>\mathrm{B}$
• C. $\mathrm{B}>\mathrm{D}>\mathrm{A}>\mathrm{C}$
• D. $\mathrm{A}>\mathrm{B}>\mathrm{C}>\mathrm{D}$

Question 3 · difficulty L2 · understanding

Given below are two statements : Statement I : The presence of weaker $$\pi$$-bonds make alkenes less stable than alkanes. Statement II : The strength of the double bond is greater than that of carbon-carbon single bond. In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are correct.
• B. Both Statement I and Statement II are incorrect.
• C. Statement I is correct but Statement II is incorrect.
• D. Statement I is incorrect but Statement II is correct.

Question 4 · difficulty L2 · understanding

In $$\mathop C\limits^1 {H_2} = \mathop C\limits^2 = \mathop C\limits^3 H - \mathop C\limits^4 {H_3}$$ molecule, the hybridization of carbon 1, 2, 3 and 4 respectively, are :

• A. sp 2 , sp, sp 2 , sp 3
• B. sp 2 , sp 2 , sp 2 , sp 3
• C. sp 3 , sp, sp 3 , sp 3
• D. sp 2 , sp 3 , sp 2 , sp 3

Question 5 · difficulty L2 · understanding

In the given reactions, identify the reagent A and reagent B.

• A. $$\mathrm{A}-\mathrm{CrO}_3 \quad \mathrm{~B}-\mathrm{CrO}_3$$
• B. $$\mathrm{A}-\mathrm{CrO}_3 \quad \mathrm{~B}-\mathrm{CrO}_2 \mathrm{Cl}_2$$
• C. A- $$\mathrm{CrO}_2 \mathrm{Cl}_2 \quad \mathrm{~B}-\mathrm{CrO}_3$$
• D. $$\mathrm{A}-\mathrm{CrO}_2 \mathrm{Cl}_2 \quad \mathrm{~B}-\mathrm{CrO}_2 \mathrm{Cl}_2$$

Question 6 · difficulty L2 · understanding

The cycloalkene $(\mathrm{X})$ on bromination consumes one mole of bromine per mole of $(\mathrm{X})$ and gives the product $(\mathrm{Y})$ in which $\mathrm{C}: \mathrm{Br}$ ratio is 3:1. The percentage of bromine in the product $(\mathrm{Y})$ is $\_\_\_\_$ %. (Nearest integer) (Given : molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{O}: 16, \mathrm{Br}: 80$ )

Question 7 · difficulty L2 · understanding

The major product of the following reaction is

• A. a hemiacetal
• B. an acetal
• C. an ether
• D. an ester

Question 8 · difficulty L3 · understanding

The total number of alkenes possible by dehydrobromination of 3-bromo-3-cyclopentylhexane using alcoholic KOH is _______.

Question 9 · difficulty L3 · understanding

$$\text {Arrange the following alkenes in decreasing order of stability. }$$ Choose the correct answer from the options given below:

• A. III $>$ I $>$ II $>$ IV
• B. III $>$ II $>$ I $>$ IV
• C. I $>$ III $>$ II $>$ IV
• D. $\mathrm{I}>\mathrm{III}>\mathrm{IV}>\mathrm{II}$

Question 10 · difficulty L3 · understanding

The reactions which cannot be applied to prepare an alkene by elimination, are Choose the correct answer from the options given below:

• A. B & E Only
• B. B, C & D Only
• C. A, C & D Only
• D. B & D Only