What is stoichiometric coefficient of Ca in the following reaction? `Ca + Al^(3+) to Ca^(2+) + Al `

Options

A. `1`
B. `1.5`
C. `2`
D. `3`

Answer

To determine the stoichiometric coefficient of calcium (Ca) in the given reaction, we will follow these steps:

### Step 1: Write the unbalanced equation
The unbalanced chemical reaction is:
\[ \text{Ca} + \text{Al}^{3+} \rightarrow \text{Ca}^{2+} + \text{Al} \]

### Step 2: Identify oxidation and reduction
In this reaction:
- Calcium (Ca) is oxidized to calcium ions (Ca²⁺) by losing 2 electrons.
- Aluminum ions (Al³⁺) are reduced to aluminum (Al) by gaining 3 electrons.

### Step 3: Balance the electrons
To balance the reaction, we need to ensure that the total number of electrons lost in oxidation equals the total number of electrons gained in reduction.

- Calcium loses 2 electrons:
\[ \text{Ca} \rightarrow \text{Ca}^{2+} + 2e^{-} \]
- Aluminum gains 3 electrons:
\[ \text{Al}^{3+} + 3e^{-} \rightarrow \text{Al} \]

### Step 4: Find the least common multiple (LCM)
The least common multiple of 2 (from Ca) and 3 (from Al) is 6. Therefore, we will need:
- 3 calcium atoms to provide 6 electrons (3 × 2 = 6).
- 2 aluminum ions to consume 6 electrons (2 × 3 = 6).

### Step 5: Write the balanced equation
Now we can write the balanced equation:
\[ 3 \text{Ca} + 2 \text{Al}^{3+} \rightarrow 3 \text{Ca}^{2+} + 2 \text{Al} \]

### Step 6: Identify the stoichiometric coefficient of Ca
In the balanced equation, the stoichiometric coefficient of calcium (Ca) is 3.

### Final Answer
The stoichiometric coefficient of Ca in the reaction is **3**.

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