The shape of electrophile which attacks on benzene nucleus in the Friedel-Craft's alkylation (methylation) reaction is
linear
planar
pyramidal
tetrahedral
Consider the following carbocations-
I. (CH3)2CH+
II. CH3CH
III. C6H5CH
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
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
D.
i<iv <iii < ii
Since alkyl groups are electron donating and the + I effect of alkyl groups on a saturated carbon chain follows the order
(CH3)3C -> (CH3)2CH -> CH3CH2 -> CH3-
However, when alkyl group is attached to benzene ring, the order of + I-effect is reversed and known as hyperconjugation effect.
CH3>-CH2CH2> (CH3)2CH-> (CH3)C. Thus, alkyl groups release electrons and increase the basic strength of aniline in the following order
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