Oxidation state of hydrogen in `CaH_(2)` is -

Options

A. `+1`
B. `-1`
C. `+2`
D. 0

Answer

To determine the oxidation state of hydrogen in calcium hydride (CaH₂), we can follow these steps:

### Step 1: Identify the oxidation state of calcium
Calcium (Ca) is an alkaline earth metal located in Group 2 of the periodic table. The common oxidation state of calcium is +2.

### Step 2: Set up the equation for the compound
In the compound CaH₂, we have one calcium atom and two hydrogen atoms. The total charge of the compound must equal zero because it is neutral.

### Step 3: Assign variables for unknown oxidation states
Let the oxidation state of hydrogen be represented by the variable \( x \). Since there are two hydrogen atoms, their total contribution to the oxidation state will be \( 2x \).

### Step 4: Write the equation based on the total charge
The equation based on the oxidation states can be written as:
\[ \text{Oxidation state of Ca} + \text{Total oxidation state of H} = 0 \]
Substituting the known values:
\[ +2 + 2x = 0 \]

### Step 5: Solve for \( x \)
To find the value of \( x \), rearrange the equation:
\[ 2x = -2 \]
Now, divide both sides by 2:
\[ x = -1 \]

### Conclusion
The oxidation state of hydrogen in calcium hydride (CaH₂) is -1.

---