The simplest formula of a compound containing 50% of an element `X` (atomic weight 10) and 50% of element `Y` (atomic weight 20) is:

Options

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

Explanation

To determine the simplest formula of a compound containing 50% of element X (atomic weight 10) and 50% of element Y (atomic weight 20), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Percentage Composition**:
- The compound contains 50% of element X and 50% of element Y.

2. **Convert Percentage to Mass**:
- Assume we have 100 grams of the compound.
- Mass of element X = 50% of 100 g = 50 g
- Mass of element Y = 50% of 100 g = 50 g

3. **Calculate Moles of Each Element**:
- Moles of element X = Mass of X / Atomic weight of X
\[ \text{Moles of X} = \frac{50 \text{ g}}{10 \text{ g/mol}} = 5 \text{ moles} \]
- Moles of element Y = Mass of Y / Atomic weight of Y
\[ \text{Moles of Y} = \frac{50 \text{ g}}{20 \text{ g/mol}} = 2.5 \text{ moles} \]

4. **Determine the Mole Ratio**:
- The mole ratio of X to Y is:
\[ \text{Ratio of X:Y} = \frac{5 \text{ moles}}{2.5 \text{ moles}} = 2:1 \]

5. **Write the Simplest Formula**:
- Based on the mole ratio, the simplest formula of the compound can be written as:
\[ \text{Formula} = X_2Y_1 \text{ or simply } X_2Y \]

### Final Answer:
The simplest formula of the compound is \( X_2Y \).

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