Question

1. which of the following is a balanced version of this equation: h2 + o2→ h2o a) 2h2 + o2 → 2h2o b) h2 + 2o2 → h2o c) h2 + o2 → h2o d) h2 + o2 → 2h2o

Explanation:

Step1: Count atoms in reactants

In $H_2 + O_2$, there are 2 hydrogen atoms and 2 oxygen atoms.

Step2: Check atom - counts in products for each option

• Option a: In $2H_2+O_2

ightarrow 2H_2O$, on the left - hand side, there are $2\times2 = 4$ hydrogen atoms and 2 oxygen atoms. On the right - hand side, in $2H_2O$, there are $2\times2 = 4$ hydrogen atoms and $2\times1 = 2$ oxygen atoms. This equation is balanced.

• Option b: In $H_2 + 2O_2

ightarrow H_2O$, on the left - hand side, there are 2 hydrogen atoms and $2\times2=4$ oxygen atoms. On the right - hand side, there are 2 hydrogen atoms and 1 oxygen atom. This equation is not balanced.

• Option c: In $H_2+O_2

ightarrow H_2O$, on the left - hand side, there are 2 hydrogen atoms and 2 oxygen atoms. On the right - hand side, there are 2 hydrogen atoms and 1 oxygen atom. This equation is not balanced.

• Option d: In $H_2+O_2

ightarrow 2H_2O$, on the left - hand side, there are 2 hydrogen atoms and 2 oxygen atoms. On the right - hand side, there are $2\times2 = 4$ hydrogen atoms and 2 oxygen atoms. This equation is not balanced.

Answer:

A. $2H_2 + O_2
ightarrow 2H_2O$