The oxidation number of arsenic atom in `H_(3)AsO_(4)` is :-

Options

A. `-1`
B. `-3`
C. `+3`
D. `+5`

Answer

To find the oxidation number of the arsenic atom in \( H_3AsO_4 \), we can follow these steps:

### Step 1: Assign oxidation numbers to known elements
- Hydrogen (H) typically has an oxidation number of +1.
- Oxygen (O) typically has an oxidation number of -2.

### Step 2: Set up the equation
Let the oxidation number of arsenic (As) be \( x \). In \( H_3AsO_4 \), we have:
- 3 hydrogen atoms contributing \( 3 \times (+1) = +3 \)
- 4 oxygen atoms contributing \( 4 \times (-2) = -8 \)
- The overall charge of the molecule is 0.

### Step 3: Write the equation based on the oxidation numbers
Now we can set up the equation based on the total oxidation numbers:
\[ 3 + x - 8 = 0 \]

### Step 4: Solve for \( x \)
Rearranging the equation gives:
\[ x - 5 = 0 \\ x = +5 \]

### Conclusion
The oxidation number of the arsenic atom in \( H_3AsO_4 \) is +5.

### Final Answer
Thus, the oxidation number of arsenic in \( H_3AsO_4 \) is **+5**.

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