Question

In the reaction 2H2 + O2 → __H2O, what coefficient should be placed in front of H2O to balance the reaction?
A-1
B-2
C-3
D- no coefficient is needed

Answer 1

I would try the answer A

Answer 2

Answer: The coefficient '2' must be added in front of $H_2O$

Explanation:

Every balanced chemical equation follows law of conservation of mass.

A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on the product side.

The given chemical equation follows:

$2H_2+O_2\rightarrow H_2O$

On the reactant side:

Number of hydrogen atoms = 4

Number of oxygen atoms = 2

On the product side:

Number of hydrogen atoms = 2

Number of oxygen atoms = 1

We need to add a coefficient '2' in front of $H_2O$ to make the atoms balanced on both sides of the reaction.

Hence, the coefficient '2' must be added in front of $H_2O$