Malonic acid
`overset(P_(2)O_(5))underset(150^(@)C)rarr" Foul smell"(A)overset(200^(@)C)rarr(B)+"Carbon"`
The total number of `sigma` and `P i` bonds present in compound A are :

Answer

To solve the problem, we need to determine the total number of sigma (σ) and pi (π) bonds present in compound A, which is formed from malonic acid under specific conditions.

### Step 1: Identify the structure of malonic acid
Malonic acid has the molecular formula \( C_3H_4O_4 \) and can be represented as:

\[ \text{HOOC-CH}_2\text{-COOH} \]

### Step 2: Determine the reaction conditions
When malonic acid reacts with \( P_2O_5 \) at \( 150^\circ C \), it produces a compound with the formula \( C_3O_2 \) (which is compound A) and phosphoric acid \( H_3PO_4 \).

### Step 3: Identify the structure of compound A
The compound \( C_3O_2 \) can be represented as:

\[ \text{O=C=C=O} \]

This structure indicates that there are two carbon atoms double bonded to an oxygen atom and one carbon atom double bonded to another oxygen atom.

### Step 4: Count the sigma bonds
In the structure of \( C_3O_2 \):

- Each carbon-carbon bond is a sigma bond.
- Each carbon-oxygen bond is also a sigma bond.

For \( C_3O_2 \):
- There are 2 carbon-carbon bonds (C=C).
- There are 2 carbon-oxygen bonds (C=O).

Thus, the total number of sigma bonds is:

\[ \text{Number of σ bonds} = 2 \text{ (C=C)} + 2 \text{ (C=O)} = 4 \]

### Step 5: Count the pi bonds
In the structure of \( C_3O_2 \):

- Each double bond consists of one sigma bond and one pi bond.

For \( C_3O_2 \):
- There are 2 double bonds (C=C and C=O).

Thus, the total number of pi bonds is:

\[ \text{Number of π bonds} = 2 \text{ (C=C)} + 2 \text{ (C=O)} = 4 \]

### Step 6: Calculate the total number of σ and π bonds
Now, we can find the total number of sigma and pi bonds in compound A:

\[ \text{Total number of σ and π bonds} = \text{Number of σ bonds} + \text{Number of π bonds} = 4 + 4 = 8 \]

### Final Answer
The total number of sigma and pi bonds present in compound A is **8**.

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