Question

Give the IUPAC name for each of the following:

(a)

(b)

(c)

(d)

Short answer

IUPAC name of structures are:

(a) Ethene:

(b) $2$-methyl-$1$-propene:

(c)$2-$pentene:

(d)$3$-methyl cyclobutene

Step-by-step solution

Part (a) step 1: Given Information 

We need to give the IUPAC name of below given compound:

Part (a) Step 2: Explanation

Given compound has two carbon atom and a double bond between them. As alkenes with two or three carbon atom need not specify position of double bond so IUPAC name of given compound is ethene.

Part (b) step 1: Given Information 

We need to give the IUPAC name of below given compound:

Part (b) Step 2: Explanation

• Selecting longest carbon chain containing double bond: So in given structure we have longest chain of three carbons atoms named as propene.
• We need to number carbon atoms starting from atom nearer to double bond. Now name is $1$- propene.
• We have substituent at $2$nd carbon atom. Substituent is methyl. So name of compound became$2$- methyl-$1$- propene.

Part (c) step 1: Given Information 

We need to give the IUPAC name of below given compound:

Part (c) Step 2: Explanation

• Selecting longest carbon chain containing triple bond: So in given structure we have longest chain of five carbons atoms named as pentene.

• We need to number carbon atoms starting from atom nearer to triple bond. Triple bond gets position at $2$nd carbon atom.

Hence, IUPAC name of given compound is $2$-pentene.

Part (d) step 1: Given Information 

We need to give the IUPAC name of below given compound:

Part (d) Step 2: Explanation

• Selecting longest carbon chain containing double bond: So in given structure we have longest chain of four carbons atoms forming a closed ring structure named as cyclobutene.
• We need to number carbon atoms starting from atom nearer to double bond. Now name is 1-cyclobutene.
• We have substituent at $3rd$carbon atom of ring. Substituent is methyl. So name of compound became $3-$methyl cyclobutene.

Hence, IUPAC name of given compound is$3-$methyl cyclobutene.