Organic Chemistry – Some Basic Principles and Techniques

The shape of electrophile which attacks on benzene nucleus in the Friedel-Craft's alkylation (methylation) reaction is

• linear

• planar

• pyramidal

• tetrahedral

The total number of isomers formed by C₅H₁₀ is

• 2

• 3

• 4

• 5

Consider the following carbocations-

I. (CH₃)₂CH⁺

II. CH₃CH${}_2^{+}$

III. C₆H₅CH${}_2^{+}$

IV. (CH₃)₃C⁺

The correct sequence for the stability of these is

• II < I < III < IV

• II < III < I < IV

• III < I < II < IV

• IV < III < I < II

Which of the following is not a nucleophile ?

• Water

• Sulphur trioxide

• Ammonia

• Ether

Friedel-Craft's acylation reaction involves

• nucleophilic substitution

• electrophlic substitution

• electrophilic addition

• nucleophilic addition

Which of the following represents the correct increasing order of electron pair availability on nitrogen based on hyperconjugation and + I and-I effects arising from alkyl groups?

• iv < iii < ii< i

• iv <i <iii< ii

• i< ii< iii< iv

• i<iv <iii < ii

Cyclohexane, methylcyclopentane, 1, 3-dimethyl cyclobutane and 1, 2, 3-trimethyl cyclopropane are examples of which one of the following? 

• Constitutional isomers

• Structural isomers

• Both (a) and (b)

• Structural as well as positional isomers

How many structural isomers are possible for a molecule of C₆H₁₂,composition but having at least-one carbocyclic ring?

• Seven

• Six

• Five

• None of these 

The configurations of the chiral centres in A and B are, respectively, as

• R and S

• S and R

• R and R

• S and S

IUPAC name of the compound is

• 2-methyl-6-ethyloct-1, 5-dienal

• 3-ethyl-7-methyloct-2, 6-dienal

• 7-methyl-3-ethyloct-2, 6-dienal

• None of the above