A compound of X and Y has equal mass of them. If their atomic
weights are 30 and 20 respectively. The molecular formula of compound is :-

Options

A. `X_(2)Y_(2)`
B. `X_(3)Y_(3)`
C. `X_(2)Y_(3)`
D. `X_(3)Y_(2)`

Answer

To solve the problem, we need to find the molecular formula of a compound made up of elements X and Y, given that they have equal masses and their atomic weights are 30 and 20, respectively.

### Step-by-Step Solution:

1. **Let the Mass of Each Element be 'x':**
Since the problem states that the masses of X and Y are equal, we can denote the mass of each element as 'x'.

2. **Calculate the Number of Moles of Each Element:**
- The number of moles of element X can be calculated using the formula:
\[ \text{Number of moles of X} = \frac{\text{mass of X}}{\text{atomic weight of X}} = \frac{x}{30} \]
- Similarly, for element Y:
\[ \text{Number of moles of Y} = \frac{\text{mass of Y}}{\text{atomic weight of Y}} = \frac{x}{20} \]

3. **Set Up the Ratio of Moles:**
To find the ratio of moles of X to Y, we take:
\[ \frac{\text{Number of moles of X}}{\text{Number of moles of Y}} = \frac{\frac{x}{30}}{\frac{x}{20}} = \frac{20}{30} = \frac{2}{3} \]
This means that for every 2 moles of X, there are 3 moles of Y.

4. **Determine the Molecular Formula:**
From the ratio of moles, we can express the molecular formula as:
\[ \text{Molecular formula} = X_2Y_3 \]

### Final Answer:
The molecular formula of the compound is \( X_2Y_3 \).

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