Question

When the equation,\(\text{Na} + \text{H}_2\text{O} \rightarrow \text{NaOH} + \text{H}_2\) is balanced,what is the coefficient for 'Na' ?

• A. 2
• B. 3
• C. 4
• D. 1

Answer 1

The Correct Option is A

To solve this problem, we need to balance the chemical equation:

1. Given Reaction:
The unbalanced equation is:
\( \text{Na} + \text{H}_2\text{O} \rightarrow \text{NaOH} + \text{H}_2 \)

2. Balancing the Equation:
- Sodium (Na) reacts with water (H₂O) to form sodium hydroxide (NaOH) and hydrogen gas (H₂).
- To balance, we start by balancing hydrogen (H). On the right side, there is 1 molecule of H₂, which provides 2 hydrogen atoms. Therefore, we need 2 NaOH on the left.
- Now, we balance sodium (Na). Since there are 2 sodium atoms in 2 NaOH, we need 2 sodium atoms on the left, i.e., 2 Na.
- Lastly, oxygen (O) is already balanced as it appears once on both sides.

3. The Balanced Equation:
\( 2\text{Na} + 2\text{H}_2\text{O} \rightarrow 2\text{NaOH} + \text{H}_2 \)

4. Coefficient of Na:
The coefficient of Na (sodium) in the balanced equation is 2.

Final Answer:
The correct option is (A) 2.