The empirical formula of a compound of molecular mass `120` is `CH_(2)O`. The molecular formula of the compound is :

Options

A. `C_(2)H_(4)O_(2)`
B. `C_(4)H_(8)O_(4)`
C. `C_(3)H_(6)O_(3)`
D. all of these

Answer

To find the molecular formula of a compound when given its empirical formula and molecular mass, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Empirical Formula and its Molar Mass:**
The empirical formula given is \( CH_2O \).
To calculate the molar mass of the empirical formula:
- Carbon (C) has an atomic mass of 12 g/mol.
- Hydrogen (H) has an atomic mass of 1 g/mol.
- Oxygen (O) has an atomic mass of 16 g/mol.

Therefore, the molar mass of \( CH_2O \) is:
\[ \text{Molar mass} = 12 + (2 \times 1) + 16 = 12 + 2 + 16 = 30 \text{ g/mol} \]

2. **Determine the Molecular Mass of the Compound:**
The molecular mass of the compound is given as 120 g/mol.

3. **Calculate the Ratio (n) of Molecular Mass to Empirical Formula Mass:**
To find \( n \), we use the formula:
\[ n = \frac{\text{Molecular mass}}{\text{Empirical formula mass}} = \frac{120}{30} = 4 \]

4. **Determine the Molecular Formula:**
The molecular formula can be found by multiplying the subscripts in the empirical formula by \( n \):
\[ \text{Molecular formula} = n \times CH_2O = 4 \times CH_2O = C_{(4)}H_{(8)}O_{(4)} = C_4H_8O_4 \]

5. **Final Answer:**
The molecular formula of the compound is \( C_4H_8O_4 \).

### Summary:
The molecular formula of the compound with an empirical formula of \( CH_2O \) and a molecular mass of 120 g/mol is \( C_4H_8O_4 \).

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