In the balanced reaction in which hydrogen and oxygen form water, if there are two water molecules on the product side, how many hydrogen molecules are required on the reactant side?
Answer and explanation
Correct answer: Two
The balanced equation is \(2\mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O}\). Two water molecules contain a total of four hydrogen atoms. Each \(\mathrm{H}_2\) molecule contains two hydrogen atoms, so two \(\mathrm{H}_2\) molecules are needed to provide four hydrogen atoms. One \(\mathrm{H}_2\) molecule would provide only two hydrogen atoms.
Frequently asked questions
What is the correct answer to this question?
Two
Why is this the correct answer?
The balanced equation is \(2\mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O}\). Two water molecules contain a total of four hydrogen atoms. Each \(\mathrm{H}_2\) molecule contains two hydrogen atoms, so two \(\mathrm{H}_2\) molecules are needed to provide four hydrogen atoms. One \(\mathrm{H}_2\) molecule would provide only two hydrogen atoms.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
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