The IUPAC name of `CH_3-C-= C.CH(CH_3)_2` is

Options

A. 4-methylpent-2-yne
B. 4,4' -dimethyl-2-pentyne
C. methyl isopropyl acetylene
D. 2-methyl-4-pentyne.

Explanation

To determine the IUPAC name of the compound `CH3-C≡C-CH(CH3)2`, we can follow these steps:

### Step 1: Identify the longest carbon chain
The first step in naming an organic compound is to identify the longest continuous carbon chain. In this case, the longest chain contains five carbon atoms.

### Step 2: Number the carbon chain
Next, we need to number the carbon chain in such a way that the triple bond receives the lowest possible number. Starting from the left side, we have:
1. C1: CH3
2. C2: C (triple bond)
3. C3: C
4. C4: CH (with a methyl group attached)
5. C5: CH3 (methyl group)

This gives us the numbering:
1 - 2 - 3 - 4 - 5

### Step 3: Identify the functional groups and substituents
The compound has a triple bond between C2 and C3, and there is a substituent (a methyl group) on C4.

### Step 4: Write the name of the compound
According to IUPAC nomenclature:
- The base name for a five-carbon chain is "pent".
- The position of the triple bond is indicated by the number where it starts, which is at C2, so we use "2-yne".
- The methyl group is at C4, so we add "4-methyl".

Putting it all together, the IUPAC name of the compound is **4-methylpent-2-yne**.

### Final Answer:
The IUPAC name of `CH3-C≡C-CH(CH3)2` is **4-methylpent-2-yne**.

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