Calculate the value of " x+y-z" here x,y and z are total number of non-bonded electron pair (s),pie `(pi)` bond(s) and sigma `(sigma)` bonds in hydrogen phosphite ion respectively.

Explanation

To solve the problem, we need to determine the values of \(x\), \(y\), and \(z\) for the hydrogen phosphite ion, \(H_2PO_3^-\).

### Step 1: Identify the structure of hydrogen phosphite ion
The molecular formula for hydrogen phosphite is \(H_2PO_3^-\). The structure can be visualized as follows:
- The phosphorus (P) atom is bonded to three oxygen (O) atoms.
- One of the oxygen atoms is bonded to a hydrogen (H) atom, and one oxygen carries a negative charge.

### Step 2: Count the non-bonded electron pairs (x)
In the structure:
- Each oxygen atom typically has 6 valence electrons.
- The oxygen that is bonded to hydrogen (OH) has 2 lone pairs.
- The negatively charged oxygen (O^-) has 3 lone pairs.
- The other oxygen (double bonded to phosphorus) has 2 lone pairs.

Counting the lone pairs:
- Oxygen with H: 2 lone pairs
- Oxygen with negative charge: 3 lone pairs
- Double bonded oxygen: 2 lone pairs

Total non-bonded electron pairs:
\[ x = 2 + 3 + 2 = 7 \]

### Step 3: Count the number of pi bonds (y)
In the structure, there is one double bond between phosphorus and one of the oxygen atoms. A double bond consists of one sigma bond and one pi bond.

Thus, the number of pi bonds:
\[ y = 1 \]

### Step 4: Count the number of sigma bonds (z)
Now, we will count the sigma bonds in the structure:
- The P-O double bond contributes 1 sigma bond.
- The P-O single bond contributes 1 sigma bond.
- The P-H bond contributes 1 sigma bond.
- The O-H bond contributes 1 sigma bond.
- The O with a negative charge also contributes 1 sigma bond.

Counting all the sigma bonds:
\[ z = 5 \]

### Step 5: Calculate \(x + y - z\)
Now we can substitute the values we found into the expression \(x + y - z\):
\[ x + y - z = 7 + 1 - 5 \]
\[ x + y - z = 3 \]

### Final Answer
The value of \(x + y - z\) is \(3\).

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