Module-1 (IVth Sem)

1. Which of the following is not a nucleophile?

• BF3

• OH-

• CN-

• NH3

• H2O

2.  Orbital interaction between the sigma bonds of a substituent group and a neighboring pi  orbital is known as                          

• (a) Hyperconjugation

• (b) Inductive effect

• (c) steric effect

• (d) dipole-dipole interactions

3. Heterolysis of a carbon-carbon bond gives

• [a] Carbanion

• [b] Carbocation

• [d] Both carbanion and carbocation

• [e] Free radical

4. Which  of  the atoms/groups have only – M effect?

• [a] COR, OR, COOR

• [b] Cl, CHO, NH2

• [c] NO2, CN, SO3H

• [d] OH, NR2, SR

5.    The increasing order of hyperconjugative effect of CH3-, C2H5-, (CH3)2CH- and (CH3)3C–  when one of these is attached to benzene ring is

• [a]CH3-, C2H5-, (CH3)2CH- and (CH3)3C–

• [b] (CH3)3C – , (CH3)2CH- , CH3- and C2H5-

• [c] (CH3)2CH-, (CH3)3C –, CH3-, C2H5-

• [d] (CH3)3C – , (CH3)2CH- , C2H5-and CH3-

• [e] (CH3)3C – , C2H5- , CH3- and (CH3)2CH-

6. In which C-C bond of 1-Bromobutane the inductive effect is expected to be the least?

• [a] C-Br

• [b] C1-C2

• [c] C2-C3

• [d] C3-C4

• [e] C4-C5

7. The C-C bond length of the following molecules is in the order

• (a) C 2H 6 >C 2 H 4> C 6H 6 > C 2 H 2

• (b) C 2 H 2 < C 2 H 4 < C 6 H 6 < C 2 H 6

• (c) C 6 H 6 > C 2 H 2 > C 2 H 6 > C 2 H 4

• (d) C 2 H 4 > C 6 H 6 > C 2 H 2 > C 2 H 6

• (e) C 2 H 4 > C 2 H 2 > C 6 H 6 > C 2 H 6

8. Which of the following statements is correct regarding nucleophiles?

• (a) They have an over-all positive charge

• (b) They have lone-pair of electrons

• (c) They have an unpaired electron

• (d) they have empty orbtials

• (e) they act as Llewis acids

9.      Which of the following belongs to +I group?

• (a) –OH

• (b) –OCH3

• (c) –COOH

• (d) –CH3

• (e) –CHO

10. Hyperconjugation is minimum in :

• (a)CH3-CH=CH2

• (b) CH3CH2-CH=CH2

• (c) (CH3)2-CH-CH=CH2

• (d) (CH3)2CH-C(CH3)=CH2

• (e) (CH3)3C-CH=CH2