2.2016 gm of acetaldehyde produceed 13.95 Kcal of heat on combustion. The heat of combustion of `CH_(3)CHO` will be

Options

A. 279 kcal
B. 972 kcal
C. 27.9 kcal
D. 2.79 kcal

Answer

To find the heat of combustion of acetaldehyde (CH₃CHO), we can follow these steps:

### Step 1: Determine the heat released per gram of acetaldehyde
Given that 2.2016 g of acetaldehyde produces 13.95 kcal of heat upon combustion, we can calculate the heat released per gram.

\[ \text{Heat released per gram} = \frac{13.95 \text{ kcal}}{2.2016 \text{ g}} \]

Calculating this gives:

\[ \text{Heat released per gram} = 6.34 \text{ kcal/g} \]

### Step 2: Calculate the molar mass of acetaldehyde (CH₃CHO)
The molar mass of acetaldehyde can be calculated as follows:

- Carbon (C): 12 g/mol (2 atoms)
- Hydrogen (H): 1 g/mol (4 atoms)
- Oxygen (O): 16 g/mol (1 atom)

\[ \text{Molar mass of CH}_3\text{CHO} = (2 \times 12) + (4 \times 1) + (1 \times 16) = 24 + 4 + 16 = 44 \text{ g/mol} \]

### Step 3: Calculate the heat of combustion for 1 mole of acetaldehyde
Now that we know the heat released per gram, we can find the heat released for 1 mole (44 g) of acetaldehyde.

\[ \text{Heat of combustion for 1 mole} = \text{Heat released per gram} \times \text{Molar mass} \]

Substituting the values:

\[ \text{Heat of combustion for 1 mole} = 6.34 \text{ kcal/g} \times 44 \text{ g} = 279 \text{ kcal} \]

### Conclusion
The heat of combustion of acetaldehyde (CH₃CHO) is approximately **279 kcal**.

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