A compound of mol. Wt 180 is acetyle to give a compound of mol. Wt 390. the number of amino groups in the initial compound is

Options

A. 2
B. 4
C. 5
D. 6

Explanation

To find the number of amino groups in the initial compound, we can follow these steps:

### Step 1: Identify the molecular weights
We are given:
- Molecular weight of the initial compound (MW1) = 180 g/mol
- Molecular weight of the acetylated compound (MW2) = 390 g/mol

### Step 2: Calculate the difference in molecular weight
We need to find the difference in molecular weight when the compound is acetylated:
\[ \text{Difference in mass} = MW2 - MW1 = 390 - 180 = 210 \text{ g/mol} \]

### Step 3: Determine the molecular weight of the acetyl group
The acetyl group (CH3CO) has a molecular weight of:
\[ \text{Molecular weight of CH3CO} = 12 (C) + 3 (H) + 12 (C) + 16 (O) = 43 \text{ g/mol} \]

### Step 4: Calculate the number of acetyl groups added
To find the number of acetyl groups added, we divide the difference in mass by the molecular weight of the acetyl group:
\[ \text{Number of acetyl groups} = \frac{\text{Difference in mass}}{\text{Molecular weight of acetyl group}} = \frac{210}{43} \approx 4.88 \]

### Step 5: Round to the nearest whole number
Since the number of acetyl groups must be a whole number, we round 4.88 to 5.

### Step 6: Relate the number of acetyl groups to the number of amino groups
Each acetylation corresponds to one amino group being present in the initial compound. Therefore, the number of amino groups in the initial compound is also 5.

### Final Answer
The number of amino groups in the initial compound is **5**.

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