Question

which of the following alkynes cannot be efficiently prepared by alkylation(s) of acetylene?select answer from the options below5-methyl-2-octyne1-octyne2-octyne4-methyl-2-octyne

Answer 1

1-octyne and 2-octyne cannot be efficiently prepared by alkylation of acetylene.

Step-by-step explanation:

Alkynes are hydrocarbons with a triple bond between two carbon atoms. They can be prepared by alkylation reactions, which involve adding alkyl groups to a compound. To determine which alkynes cannot be efficiently prepared by alkylation of acetylene, we need to look at the options:

1. 5-methyl-2-octyne
2. 1-octyne
3. 2-octyne
4. 4-methyl-2-octyne

Out of these options, the alkynes that cannot be efficiently prepared by alkylation of acetylene are 1-octyne and 2-octyne. This is because these compounds have alkyl groups attached to carbon atoms in the middle of the carbon chain, and it is difficult to selectively add alkyl groups at these positions using acetylene as a starting material.

Answer 2

Efficient preparation of alkynes by alkylation of acetylene depends on the availability of suitable alkylating agents. Alkylation of acetylene can efficiently produce 5-methyl-2-octyne, 1-octyne, and 4-methyl-2-octyne. However, alkylation of acetylene cannot efficiently produce 2-octyne.

Step-by-step explanation:

Efficient preparation of alkynes by alkylation of acetylene depends on the availability of suitable alkylating agents. In this case, we need to consider the structure of the alkyne and the alkylating agent. Alkylation of acetylene can efficiently produce 5-methyl-2-octyne, 1-octyne, and 4-methyl-2-octyne. However, the alkylation of acetylene cannot efficiently produce 2-octyne. This is because the alkyl group would need to be attached to the internal carbon atom of the triple bond, which is less stable than the terminal carbon atom.