Question

Which of the following chemical equation satisfies the law of conservation of mass?

• A. $C+O_2\to C{O}_2$
• B. $2C+O_2\to C{O}_2$
• C. $4C+O_2\to C{O}_2$
• D. $C+2O_2\to C{O}_2$

Answer 1

The correct option is A

$C+O_2\to C{O}_2$

Law of conservation of mass states that mass cannot be created or destroyed. It can change forms but is conserved.
Hence, in a chemical reaction, the mass of the products equals the mass of the reactants. This is only possible if the chemical equation is correctly balanced.
The only reaction which is balanced is:
$C+O_2\to C{O}_2$

LHS$\to$ ($C+O_2$) $\to$ 1 C + 2 O

RHS$\to$ ($C{O}_2$) $\to$ 1 C + 2 O
So, option A follows the law of conservation of mass.