What is the IUPAC name of the following compound?

Step 1: Identify the structure from the image

Structure: $\ce{CH3-C(CH3)=C(H)-CH(Br)-CH3}$

Step 2: Find the longest carbon chain

Longest chain: 5 carbons → pentane

Step 3: Number the chain

Rule: Give the double bond the lowest number.

• Numbering from left: Double bond at C-2
• Numbering from right: Double bond at C-3

Choose left to right: C-2 has the double bond (lower number)

C1: CH3
C2: C (with CH3 substituent)
C3: C (double bond to C2)
C4: CH (with Br substituent)  
C5: CH3

Step 4: Identify substituents

• Bromine at C-4: 4-bromo
• Methyl at C-3: 3-methyl
• Double bond between C-2 and C-3: pent-2-ene

Step 5: Write IUPAC name

Alphabetical order: bromo before methyl

4-Bromo-3-methylpent-2-ene

Answer: (d)

Key IUPAC Rules:

1. Longest carbon chain with functional group
2. Number to give functional group (double bond) lowest number
3. Name substituents alphabetically
4. Use hyphens between numbers and words, commas between numbers