#### 11th Standard Chemistry Basic Concept of Organic Reactions English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Chemistry

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. What is the hybridisation state of benzyl carbonium ion ?

(a)

sp2

(b)

spd2

(c)

sp3

(d)

sp2d

2. Which of the following species is not electrophilic in nature ?

(a)

Cl+

(b)

BH3

(c)

H3O+

(d)

+NO2

3. Hyper Conjugation is also known as ___________.

(a)

no bond resonance

(b)

Baker - nathan effect

(c)

both (a)and (b)

(d)

none of these

4. Which of the following species does not exert a resonance effect ?

(a)

C6H5OH

(b)

C6H5Cl

(c)

C6H5NH2

(d)

${ C }_{ 6 }{ H }_{ 5 }\overset { + }{ N } { H }_{ 3 }$

5. Which of the following carbocation will be most stable ?

(a)

Ph3C-+

(b)

${ C }{ H }_{ 3 }-\overset { + }{ C } { H }_{ 2 }$

(c)

$\left( { CH }_{ 3 } \right) _{ 2 }-\overset { + }{ C } { H }$

(d)

$CH_{ 2 }=CH-\overset { + }{ C } { { H }_{ 2 } }$

6. Heterolytic fission of C-C bond results in the formation of _____________.

(a)

(b)

Carbanion

(c)

Carbocation

(d)

Carbanion and Carbocation

7. Which of the following species does not acts as a nucleophile ?

(a)

ROH

(b)

ROR

(c)

PCl3

(d)

BF3

8. Which of the following is heterolytic compound?

(a)

Pyrrole

(b)

Furan

(c)

Thiophene

(d)

All of these

9. The most stable carbanion is _____________

(a)

CH3-CH2

(b)

CH2 = CH

(c)

CH≡ C

(d)

(CH3)2 - CH

10. In -NO2, -NH2, -SO3H, the decreasing order of I II III -I effect is ___________

(a)

I > II > III

(b)

I > III > II

(c)

III > II > I

(d)

III > I > II

11. The nucleophile is not ___________

(a)

Lewis base

(b)

Lewis acid

(c)

${ H }_{ 2 }\overset { .. }{ \underset { .. }{ O } }$

(d)

Carbanion

12. Which of the following statements is not correct for a nucleophile ?

(a)

Nucleophiles attack low electron density sites

(b)

Nucleophiles are not electron seeking

(c)

Nucleophiles is a Lewis acid

(d)

Ammonia is a nucleophile

13. Assertion (A) : Phenol is less acidic than benzoic acid.
Reason (R) : Phenoxide has less number of resonating structures that benzyl carboxylate ion.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not correct explanation of A.
(c) A is true statement but R is false.
(d) Both A and R are false.

(a)

Both A and R are true and R is the correct explanation of A.

(b)

Both A and R are true but R is not correct explanation of A.

(c)

A is true statement but R is false.

(d)

Both A and R are false.

14. The electrometric effect is ___________

(a)

Permanent effect

(b)

Temporary effect

(c)

p-electrons transfer in the effect

(d)

Both (b) and (c)

15. Which one is incorrect match of reactions ?

(a)

(b)

$C{ H }_{ 3 }-C{ H }_{ 2 }-Br\overset { aq.\quad KOH }{ \longrightarrow } C{ H }_{ 3 }-C{ H }_{ 2 }OH$ ⟶ Nucleophilic substitution reaction

(c)

(d)

$\left( C{ H }_{ 3 } \right) C-Cl\overset { \overset { + }{ H } }{ \longrightarrow } { \left( C{ H }_{ 3 } \right) }_{ 3 }C-C{ H }_{ 2 }+{ H }_{ 2 }O+{ Cl }^{ - }$ ⟶ Nucleophilic substitution reaction

16. The stability of alkyl free radicals is due to ___________

(a)

Hyperconjugation

(b)

+I effect

(c)

-I effect

(d)

Both a & b

17. Which of the following compounds will not undergo Friedal-craft's reaction easily ?

(a)

Xylene

(b)

Nitrobenzene

(c)

Toluene

(d)

Cumene

18. Assertion (A) : $C{ H }_{ 3 }-\overset { + }{ C } H-C{ H }_{ 3 }$ has 6 hyper-conjugative hydrogens. While $C{ H }_{ 3 }-\overset { + }{ C } H-C{ H }_{ 2 }-C{ H }_{ 3 }$ has 5 hyper-conjugative hydrogens.
Reason (R) : $C{ H }_{ 3 }-\overset { + }{ C } H-C{ H }_{ 3 }$ is more stable than $C{ H }_{ 3 }-\overset { + }{ C } H-C{ H }_{ 2 }-C{ H }_{ 3 }$
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) Both A and R are false.

(a)

Both A and R are true and R is the correct explanation of A.

(b)

Both A and R are true but R is not the correct explanation of A.

(c)

A is true but R is false.

(d)

Both A and R are false

19. Assertion (A) : Phenol is less acidic than benzoic acid.
Reason (R) : Phenoxide has less number of resonating structures than benzyl carboxylate ion.

(a)

Both A and R are true and R is the correct explanation of A.

(b)

Both A and R are true but R is not the correct explanation of A.

(c)

A is true but R is false.

(d)

Both A and R are false.

20. Which one of the following is positively charged electrophiles ?

(a)

CO2

(b)

AlCl3

(c)

BF3

(d)

RX