Haloalkanes and Haloarenes Test

Result

Haloalkanes and Haloarenes Test - 50

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

$$(+)-$$ Mandelic acid has a specific rotation of $$+158^o$$ . What would be the observed specific rotation of a mixture of $$25\%$$ $$(-)-$$ mandelic acid and $$75\% (+)-$$ mandelic acid:

A
$$+118.5^o$$

B
$$-118.5^o$$

C
$$-79^o$$

D
$$+79$$

Solution

Concentration of (-) Mandelic acid= $$25$$%
Concentration of (+) Mandelic acid= $$75$$%
$$\therefore$$ Excess of (+) Mandelic acid= $$75-25=50$$%
Enantiomeric excess= $$\cfrac {\text {Observed specific rotation}}{\text{(sp. rotation of pure (+) enantiomer)}}\times 100$$%
$$\Rightarrow 50= \cfrac {x}{158}\times 100$$
$$\therefore x$$ = observed specific rotation= $$+79$$
Question 2
1 / -0

Which of the following halide undergoes in hydrolysis via $${S}_{{N}^{1}}$$ reaction?

A
$$B{Cl}_{3}$$

B
$${NF}_{3}$$

C
$$N{Cl}_{3}$$

D
$$As{Cl}_{3}$$

Solution

Under ordinary conditions, $$N{ F }_{ 3 }$$ does not hydrolyses via $${ S }_{ { N }_{ 2 } }$$mechanism because $${ H }_{ 2 }O$$ (which should act as a nucleophile) cannot attack any of Nitrogen or Fluorine atom due to absence of vacant orbitals of suitable energy.
But, under drastic conditions it gives $$N_{ 2 }O_{ 3 }$$ and $$HF$$ via series of reactions involving 3 times $${ S }_{ { N }_{ 1 } }$$ with deprotonation and then 2 times dehydration.
Question 3
1 / -0

$$CH_3CH=CH_2 \xrightarrow {Cl-I} P$$, $$P$$ is:

A
$$CH_3-CHI-CH_2Cl$$

B
$$CH_3CHCl-CH_2I$$

C
$$CH_3-ICHCl-CH_2$$

D
$$CH_3-CH_2-ICHCl$$

Solution

$$CH_3-CH=CH_2 \xrightarrow {I^+- \ Cl^-} CH_3-CHCl-CH_2-I$$

The reaction is electrophilic addition and the product obtained is called Markonikov product.
Question 4
1 / -0

Which of the following reaction is used to increase the length of the carbon chain ?

A
Clemmensen reduction

B
Wolff-Kishner Reduction

C
Wurtz reaction

D
Kolbe’s electrolysis
Question 5
1 / -0

The reaction of Sodium methoxide with $${R}_{2}CHX$$ is:

A
$${SN}^{1}$$

B
$${SN}^{2}$$

C
Elimination

D
Substitution

Solution

Sodium methoxide $$\Rightarrow { CH }_{ 3 }\overset { \left( - \right) }{ O } \overset { + }{ Na } $$
As the corboncation formed is stable by inductive effect and hyper conjugation. It undergoes $${ SN }^{ 1 }$$ reaction.
$${ SN }^{ 1 }$$ reaction means the formed carboncation should be stable.
Question 6
1 / -0

$$CH_{ 3 }-\overset { \overset { CH_{ 3 } }{ | } }{ CH } -CH_{ 3 }\xrightarrow [ ]{ Cl_{ 2 } } Product$$
Major product in the above reaction is :

A
$$CH_{ 3 }-\overset { \overset { CH_{ 3 } }{ | } }{ CH } -CH_{ 2 }-Cl$$

B
$$CH_{ 3 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { Cl }{ | } }{ C } H } -CH_{ 3 }-CH_{ 3 }$$

C
$$CH_{ 3 }-CH_2-CH_2-Cl$$

D
$$CH_{ 3 }-\underset { \underset { Cl }{ | } }{ C } H-CH_{ 2 }-Cl$$
Question 7
1 / -0

Predict the major in each of the following elimination reaction:

A

B

C

D

Solution

$$\beta$$- elimination, also known as Hofmann Elimination is used to convert an amine with a $$\beta$$-hydrogen to an alkene using methyl iodide, silver oxide and water at thermal conditions. Methyl iodide coverts the amine into a quarterly salt which when heated gives an alkene, a $$3^0$$ amine and w
Question 8
1 / -0

Which of the following react with $$Cl_2$$ and $$Br_2$$ at room temperature and in the absence of diffused sunlight to produce dihalogen derivatives?

A
Cyclobutane

B
Cyclopentane

C
Cyclohexane

D
All of these

Solution

Cyclo butane on reaction with $${ Cl }_{ 2 }$$ at 298K produce dihalogen derivatives mechanism.
Question 9
1 / -0

Which one of the following compounds is not optically active?

A
$$CH_3CH_2CH(CH_3)CH_2Cl$$

B
$$CH_3CH_2CH(CH_3)$$

C
$$CH_3 - CHOH - COOH$$

D
$$CH_3 - CHCl - CH_2Br$$

Solution

$$\Rightarrow $$ Inactive due to two repetitive units of $${ CH }_{ 3 }$$
$$\Rightarrow $$ Active due to 4 different units.
$$\Rightarrow $$ Active due to 4 different units.
$$\Rightarrow $$ Active due to 4 different units.
Question 10
1 / -0

Identify the products $$A$$ and $$B$$.

A

B

C

D
None of these

Solution