Question

What is the molar ratio of hydrogen and oxygen in the formation of water ?

• A. 1:2
• B. 2:1
• C. 1:1
• D. 2:3

Answer 1

The Correct Option is B

To determine the molar ratio of hydrogen and oxygen in the formation of water, we need to analyze the chemical reaction involved.

1. Understanding the Reaction:
The formation of water involves the combination of hydrogen gas ($\text{H}_2$) and oxygen gas ($\text{O}_2$). The balanced chemical equation for this reaction is:

$$ 2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} $$

2. Identifying the Stoichiometry:
From the balanced equation:
- 2 moles of $\text{H}_2$ react with 1 mole of $\text{O}_2$ to produce 2 moles of $\text{H}_2\text{O}$.
- The molar ratio of $\text{H}_2$ to $\text{O}_2$ is therefore $2 : 1$.

3. Verifying the Options:
Let us evaluate the given options:
1. $1 : 2$: This is incorrect because it suggests that 1 mole of $\text{H}_2$ reacts with 2 moles of $\text{O}_2$, which does not match the balanced equation.
2. $2 : 1$: This matches the stoichiometry of the balanced equation.
3. $1 : 1$: This is incorrect because it suggests that equal moles of $\text{H}_2$ and $\text{O}_2$ react, which is not true.
4. $2 : 3$: This is incorrect because it does not match the stoichiometry of the balanced equation.

Final Answer: $ {2 : 1} $