In the balanced chemical equation 2H₂ + O₂ → 2H₂O for the formation of water, how many hydrogen atoms are present in total on the product side?
Answer and explanation
Correct answer: 4
The coefficient 2 before H₂O means that two water molecules are present on the product side. The subscript 2 in each H₂O molecule shows that each molecule contains two hydrogen atoms. Therefore, the total number of hydrogen atoms is coefficient × subscript = 2 × 2 = 4. The value 2 counts hydrogen atoms in only one water molecule, whereas 6 incorrectly mixes coefficients and subscripts. Thus option C is correct.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
The coefficient 2 before H₂O means that two water molecules are present on the product side. The subscript 2 in each H₂O molecule shows that each molecule contains two hydrogen atoms. Therefore, the total number of hydrogen atoms is coefficient × subscript = 2 × 2 = 4. The value 2 counts hydrogen atoms in only one water molecule, whereas 6 incorrectly mixes coefficients and subscripts. Thus option C is correct.
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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