Organic Chemistry – Some Basic Principles and Techniques · Question 20

The correct statement regarding electrophile is

1. electrophile is a negatively charged species and form a bond by accepting a pair of electrons from another electrophile
2. electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile
3. electrophile can be either neutral or positively charged species and can form a bond by accepting a pair of electrons from a nucleophile
4. electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from a nucleophile.

The IUPAC name of the compound [figure]

1. 5-formylhex-2-en-3-one
2. 5-methyl-4-oxohex-2-en-5-al
3. 3-keto-2-methylhex-5-enal
4. 3-keto-2-methylhex-4-enal

Which one is the correct order of acidity?

1. CH CH > CH3-C CH > CH2=CH2 > CH3-CH3
2. CH CH > CH2=CH2 > CH3-C CH > CH3-CH3
3. CH3-CH3 > CH2=CH2 > CH3-C CH > CH CH
4. CH2=CH2 > CH3-CH=CH2 > CH3-C CH > CH CH

For the following reactions : (A) CH3CH2CH2Br + KOH CH3CH=CH2 + KBr + H2O (B) [figure] (C) [figure] Which of the following statements is correct?

1. (A) is elimination, (B) and (C) are substitution reactions.
2. (A) is substitution, (B) and (C) are addition reactions.
3. (A) and (B) are elimination reactions and (C) is addition reaction.
4. (A) is elimination, (B) is substitution and (C) is addition reaction.

The pair of electrons in the given carbanion, CH3C C-, is present in which of the following orbitals?

1. sp2
2. sp
3. 2p
4. sp3

In which of the following molecules, atoms are coplanar?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

In pyrrole the electron density is maximum on [figure]

1. 2 and 3
2. 3 and 4
3. 2 and 4
4. 2 and 5

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

1. Ammonia is a nucleophile.
2. Nucleophiles attack low e- density sites.
3. Nucleophiles are not electron seeking.
4. Nucleophile is a Lewis acid.

The total number of π-bond electrons in the following structure is [figure]

1. 12
2. 16
3. 4
4. 8

Which of the following is the most correct electron displacement for a nucleophilic reaction to take place?

1. [figure]
2. [figure]
3. [figure]
4. [figure]