The standard heat of combustion of solid boron is equal to

Options

A. `DeltaH_(f)^(@)(B_(2)O_(3))`
B. `1//2DeltaH_(f)^(@)(B_(2)O_(3))`
C. `2DeltaH_(f)^(@)(B_(2)O_(3))`
D. `-1//2DeltaH_(f)^(@)(B_(2)O_(3))`

Explanation

To find the standard heat of combustion of solid boron, we can follow these steps:

### Step-by-Step Solution:

1. **Write the Combustion Reaction**:
The combustion of solid boron (B) in the presence of oxygen (O₂) produces boron trioxide (B₂O₃). The unbalanced reaction can be written as:
\[ B + O_2 \rightarrow B_2O_3 \]

2. **Balance the Reaction**:
To balance the equation, we need to ensure that the number of atoms of each element on the reactant side equals the number on the product side. The balanced equation for the combustion of boron is:
\[ 4B + 3O_2 \rightarrow 2B_2O_3 \]

3. **Convert to Moles of Solid Boron**:
Since we are interested in the standard heat of combustion for 1 mole of solid boron, we can express the balanced equation in terms of 1 mole of boron:
\[ B + \frac{3}{4}O_2 \rightarrow \frac{1}{2}B_2O_3 \]

4. **Determine the Standard Heat of Combustion**:
The standard heat of combustion (ΔH°_combustion) for boron can be related to the standard heat of formation (ΔH°_formation) of boron trioxide. According to the reaction, the heat of combustion for 1 mole of boron is half of the heat of formation of B₂O₃:
\[ \Delta H°_{combustion} = \frac{1}{2} \Delta H°_{formation} \text{ of } B_2O_3 \]

5. **Identify the Correct Option**:
Based on the above calculations, we can conclude that the standard heat of combustion of solid boron is equal to half of the standard heat of formation of B₂O₃. If the problem provides specific values for the standard heat of formation, you can substitute that value to find the exact heat of combustion.