Find the odd one out with respect to valency.

Options

A. Ferrous
B. Mercurous
C. Stannous
D. Cupric

Explanation

To solve the question of finding the odd one out with respect to valency, we need to analyze the valencies of the given elements. Let's break it down step by step.

### Step 1: Identify the Elements and Their Valencies
We need to identify the elements mentioned in the question and their respective valencies. The elements discussed are:
1. Ferrous (Iron, Fe)
2. Mercury (Hg)
3. Stannous (Tin, Sn)
4. Cupric (Copper, Cu)

### Step 2: Determine the Valency of Each Element
- **Ferrous (Fe)**: The valency of ferrous is +2.
- **Mercury (Hg)**: The valency of mercury is +1.
- **Stannous (Sn)**: The valency of stannous is +2.
- **Cupric (Cu)**: The valency of cupric is +2.

### Step 3: Compare the Valencies
Now, we will compare the valencies of all the elements:
- Ferrous (Fe): +2
- Mercury (Hg): +1
- Stannous (Sn): +2
- Cupric (Cu): +2

### Step 4: Identify the Odd One Out
From the comparison:
- Ferrous, Stannous, and Cupric all have a valency of +2.
- Mercury has a valency of +1.

Thus, the element that does not match the others in terms of valency is **Mercury (Hg)**.

### Conclusion
The odd one out with respect to valency is **Mercury (Hg)**.

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