NCERT Class XI Chemistry Hydrocarbons Solutions
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Question : 6
Total: 25
An alkene A contains three C – C, eight C – H σ-bonds and one C – C π-bond. A on ozonolysis gives two moles of an aldehyde of molar mass 44 u. Write the IUPAC name of A.
Solution:
A is an alkene. A contains (i) 3 C – C σ-bonds, (ii) 8 C – H σ-bonds and (iii) 1 C – C π bond.
(A)
Molar mass of RCHO = 44u
(i) The clue to finding the structure and therefore the IUPAC name of A lies in the aldehyde RCHO.
The mass of – CHO group is 29 u. This implies that the alkyl group attached has a mass of 44 – 29 = 15. This can be the mass of –CH3 group only.
∴ RCHO isC H 3 C H O
(ii) Since 2 moles of only CH3CHO is obtained. Therefore, the alkene is
H 3 C −
= O O =
− C H 3
Thus, (A) isC H 3 – H C = C H – C H 3
This structure also confirms the given number of σ and π bonds.
(A)
Molar mass of RCHO = 44u
(i) The clue to finding the structure and therefore the IUPAC name of A lies in the aldehyde RCHO.
The mass of – CHO group is 29 u. This implies that the alkyl group attached has a mass of 44 – 29 = 15. This can be the mass of –CH3 group only.
∴ RCHO is
(ii) Since 2 moles of only CH3CHO is obtained. Therefore, the alkene is
Thus, (A) is
This structure also confirms the given number of σ and π bonds.
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