Correct Answer - Option 3 : 2
The correct answer is 2.
Concept:
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The Law of conservation of mass states that matter can neither be created nor destroyed.
- In a chemical reaction, new compounds different from the starting materials are formed.
- In accordance with the law of conservation of mass, thus the number of atoms of each element in the reactant and product side will be the same.
So, we need to balance the chemical equation.
Calculation:
To balance a chemical reaction:
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Check the number of atoms before and after the reaction.
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Balance the elements one at a time by adding coefficients before them.
- Change the coefficients as required.
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Never change the subscripts.
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PbO + 2HCl → PbCl2 + H2O is the balanced equation.
- The balance of the above equation requires 2 moles of HCl.
Hence, 2 moles is correct.
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Balanced chemical equation:
- A chemical equation in which the number of each type of atom is equal on the two sides of the equation.