Question
Question: The stability if \(M{e_2}C = C{H_2}\) is more than that of \(MeC{H_2}CH = C{H_2}\) due to A. Indu...
The stability if Me2C=CH2 is more than that of MeCH2CH=CH2 due to
A. Inductive effect due to Me group
B. Resonance effect due to Me group
C. Hyperconjugation effect due to Me group
D. Resonance as well inductive effect due to Me group
Solution
Hint- In order to deal with this question first we will understand the term hyperconjugation further according to its property we will determine which compound has more hyperconjugation amongst the given compounds on the basis of the criterion for comparison.
Complete step-by-step answer:
Hyperconjugation effect is a lasting phenomenon under which the position of C−H bond of an alkyl group immediately attached to an unsaturated cell atom or an unshared p orbital atom exists.
We also note that hyperconjugation helps to balance the carbocation as it helps to distribute positive charge. Therefore we can assume that the greater the number of alkyl groups bound to a positively charged carbon atom, the greater the relationship between hyperconjugation and carbocation stabilization
Now, In Me2C=CH2 with respect to Alkene the number of α− Hydrogen atoms are 6
(i.e. the number of hydrogen atoms taking part in hyperconjugation).
While in MeCH2CH=CH2 , the number of α− Hydrogen atoms are 2.
So, the extent of hyperconjugation is more in
Me2C=CH2 than in MeCH2CH=CH2
Thus, Me2C=CH2 is more stable than MeCH2CH=CH2 .
Hence, the stability if Me2C=CH2 is more than that of MeCH2CH=CH2 due to Hyperconjugation effect due to Me group.
So, the correct answer is option C.
Note- The resonance effect is the polarity created by the interaction of a lone electron pair with a pi bond in a molecule, or the interaction of two pi bonds in neighboring atoms. It is commonly found in double-bonded conjugated molecules or in at least one lone pair and one double bonded molecule.
The inductive effect is an effect on the transfer of uneven bonding electron sharing through a series of atoms in a molecule, resulting in a permanent dipole in a bond.