The oxidation state of phosphorus is maximum is

Options

A. Phospine `(PH_3)`
B. Diphosphine `(P_2H_4)`
C. Metaphosphoric acid `(HPO_3)`
D. Phosphorus acid `(H_3PO_3)`

Answer

To determine the maximum oxidation state of phosphorus, we can analyze various compounds of phosphorus and calculate the oxidation states. Here’s a step-by-step solution:

### Step 1: Understanding Oxidation State
The oxidation state (or oxidation number) of an element in a compound indicates the degree of oxidation of that element. It can be positive, negative, or zero, depending on the nature of the compound.

### Step 2: Analyzing Phosphine (PH₃)
In phosphine (PH₃):
- The oxidation state of hydrogen (H) is +1.
- Let the oxidation state of phosphorus (P) be x.
- The overall charge of the molecule is 0.

Setting up the equation:
\[ x + 3(+1) = 0 \]
\[ x + 3 = 0 \]
\[ x = -3 \]

So, the oxidation state of phosphorus in phosphine is -3.

### Step 3: Analyzing Diphosphine (P₂H₄)
In diphosphine (P₂H₄):
- The oxidation state of hydrogen is +1.
- Let the oxidation state of phosphorus be x. Since there are two phosphorus atoms, the total contribution is 2x.

Setting up the equation:
\[ 2x + 4(+1) = 0 \]
\[ 2x + 4 = 0 \]
\[ 2x = -4 \]
\[ x = -2 \]

So, the oxidation state of phosphorus in diphosphine is -2.

### Step 4: Analyzing Metaphosphoric Acid (HPO₃)
In metaphosphoric acid (HPO₃):
- The oxidation state of hydrogen is +1.
- The oxidation state of oxygen is -2.
- Let the oxidation state of phosphorus be x.

Setting up the equation:
\[ x + 1 + 3(-2) = 0 \]
\[ x + 1 - 6 = 0 \]
\[ x - 5 = 0 \]
\[ x = +5 \]

So, the oxidation state of phosphorus in metaphosphoric acid is +5.

### Conclusion
The maximum oxidation state of phosphorus is +5, which occurs in metaphosphoric acid (HPO₃).

---