Two elements A (Atomic Mass 12 g/mole) and B (Atomic Mass 16 g/mole) combine to yield a compound. The percentage mass of A in the compound is `27.3%`. The formula of the compound will be :

Options

A. `A_(2)B_(2)`
B. AB
C. `A_(2)B`
D. `AB_(2)`

Answer

To find the formula of the compound formed by elements A and B, we can follow these steps:

### Step 1: Determine the mass of A and B in the compound
Given that the percentage mass of A in the compound is 27.3%, we can assume a total mass of the compound to be 100 grams for simplicity.

- Mass of A = 27.3% of 100g = 27.3 g
- Mass of B = 100 g - 27.3 g = 72.7 g

### Step 2: Calculate the number of moles of A and B
To find the number of moles, we use the formula:

\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mole)}} \]

- Moles of A = \(\frac{27.3 \text{ g}}{12 \text{ g/mole}} = 2.275 \text{ moles}\)
- Moles of B = \(\frac{72.7 \text{ g}}{16 \text{ g/mole}} = 4.54375 \text{ moles}\)

### Step 3: Determine the mole ratio of A to B
Now we need to find the simplest whole number ratio of moles of A to moles of B.

- Ratio of A to B = \(\frac{4.54375 \text{ moles of B}}{2.275 \text{ moles of A}} \approx 2\)

This means the ratio of B to A is approximately 2:1.

### Step 4: Write the empirical formula
From the mole ratio, we can deduce that for every 1 mole of A, there are 2 moles of B. Therefore, the empirical formula of the compound is:

\[ \text{AB}_2 \]

### Conclusion
The formula of the compound formed by elements A and B is \( \text{AB}_2 \).

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