Question

Give the IUPAC name for each of the following :

Short answer

a. The IUPAC name of the compound is $ethene$.

b. The IUPAC name of the compound is $2-methylpropene$.

c. The IUPAC name of the compound is $2-pentyne$.

d. The IUPAC name of the compound is $3-methylcyclobutene$.

Step-by-step solution

Part (a) Step 1 : Given information

We have to write the IUPAC name of the given compound i.e.

Part (a) Step 2 : Simplification

We know that

• There are two carbon in the parent chain so the word root will be $eth$
• It contains unsaturated double bond so the primary suffix will be $ene$

Hence the IUPAC name of the compound will be $ethene$

Part (b) Step 1 : Given information

We have to write the IUPAC name of the given compound i.e.

Part (b) Step 2 : Simplification

We know that

• The parent chain of the given compound is of three carbon so the word root will be $prop$
• It also contains an unsaturated double bond so the primary suffix will be $ene$-
• It also contains one $methyl$as the chain on the second carbon of the parent chain.

Hence its IUPAC name is $2-methylpropene$.

Part (c) Step 1 : Given information

We have to write the IUPAC name of the given compound i.e.

Part (c) Step 2 : Simplification

We know that

• The parent chain of the given compound is of five carbon so the word root will be $\mathrm{pent}$
• It also contains an unsaturated triple bond between the second and third carbon of the parent chain so the primary suffix will be $2-yne$.

Hence It's IUPAC name is $2-pentyne$

Part (d) Step 1 : Given information

We have to write the IUPAC name of the given compound i.e.

Part (d) Step 2 : Simplification

We know that

• The given compound is a four-membered ring so its infix is $cyclo$and word root is $\mathrm{but}$
• It also contains unsaturation of double bond so its primary suffix is $ene$
• It also contains a $methyl$at third carbon of the cyclic ring.

Hence its IUPAC name is $3-methylcyclobutene$