The valency of `Cr` in the complex `[Cr(H_(2)O)_(4)Cl_(2)]^(+)`

Options

A. `1`
B. `3`
C. `5`
D. `6`

Explanation

To determine the valency (oxidation state) of chromium (Cr) in the complex \([Cr(H_2O)_4Cl_2]^+\), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the components of the complex:**
- The complex consists of 4 water molecules (H₂O) and 2 chloride ions (Cl⁻).
- The overall charge of the complex is +1.

2. **Assign oxidation states:**
- The oxidation state of water (H₂O) is 0 because it is a neutral molecule.
- The oxidation state of each chloride ion (Cl⁻) is -1.

3. **Set up the equation:**
- Let the oxidation state of chromium (Cr) be \(X\).
- The contribution to the overall charge from the water molecules is \(4 \times 0 = 0\).
- The contribution from the two chloride ions is \(2 \times (-1) = -2\).
- The overall charge of the complex is +1.

Therefore, we can set up the equation:
\[ X + 0 + (-2) = +1 \]

4. **Solve for \(X\):**
- Rearranging the equation gives:
\[ X - 2 = 1 \]
\[ X = 1 + 2 \]
\[ X = 3 \]

5. **Conclusion:**
- The valency (oxidation state) of chromium (Cr) in the complex \([Cr(H_2O)_4Cl_2]^+\) is +3.