#### Basic concept of organic reactions Model Question Paper

11th Standard

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Chemistry

Time : 02:00:00 Hrs
Total Marks : 50
5 x 1 = 5
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. Which of the group has highest +I effect?

(a)

CH3-

(b)

CH- CH-

(c)

(CH3)2 - CH-

(d)

(CH3)3 - C-

4. 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)

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

5. The geometrical shape of carbocation is

(a)

Linear

(b)

tetrahedral

(c)

Planar

(d)

Pyramidal

6. 5 x 1 = 5
7. The slowest step in the mechanism determines_________

()

Rate of reaction

8. During the cleavage of Azobisisobutyronitrile produces,______species

()

9. The cleavage of C-H bond in aldehydes leads to formation of_______

()

Carbanion

10. Example for positive mesomeric effect is_________

()

-OH

11. Alcohol on refluxing with K2Cr2O7 gives________

()

Carboxylic acid

12. 2 x 2 = 4
13. Assertion (A): The C- C bond in ethane is non-polar while the C- C bond in ethyl chloride is polar.
Reason (R): Chlorine is more electronegative than carbon and hence it attracts the shared pair of electron between C - Cl in ethyl chloride and it develops a negative charge on Cl and positive charge on Carbon.
(a) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(b) Both (A) and (R) arecorrect and (R) is the correct explanation of (A).
(c) (A) is correct but (R) is wrong.
(d) (A) is wrong but (R) is correct.

14. Assertion (A): The cut apple turns brown.
Reason (R): Cut apple exposes its cells to atmospheric oxygen and the oxidises the phenolic compound present in it. Due to this enzymatic browning, the cut apple turns brown.
(a) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(b) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(c) (A) is correct but (R) is wrong.
(d) (A) is wrong but (R) is correct.

15. 2 x 2 = 4
16. (a) NH3
(b) H2O
(c) CN-
(d) RSH

17. (a) - C(CH3)3
(b) - COOH
(c) - CH(CH3)2
(d) - COO

18. 8 x 2 = 16
19. What are electrophiles and nucleophiles? Give suitable examples for each.

20. Explain inductive effect with suitable example.

21. Explain electromeric effect.

22. Draw the resonating structure of C6H5NH2 .

23. Define resonance effect.

24. Why does SO3 act as an electrophile?

25. Mention the types of fission of a covalent bond?

26. What are carbocations?

27. 2 x 3 = 6
28. Distinguish between electrophiles and nucleophiles

29. Explain the substitution reaction in detail with suitable examples.

30. 2 x 5 = 10
31. Explain electron movement in organic reactions.

32. Explain the types of addition reactions?