Answer
Balanced chemical equation:
$3NO_2(g) + H_2O(g) --\gt 2HNO_3(g) + NO(g)$
Work Step by Step
1. Identify the reactants and products, and write the unbalanced equation:
Reactants: $NO_2$ and water in the air : $H_2O(g)$
Products: $HNO_3$ and nitrogen oxide: $NO$
$NO_2(g) + H_2O(g) --\gt HNO_3(g) + NO(g)$
2. Balance the number of hydrogen atoms, by putting a "2" as the coefficient of $HNO_3$
$NO_2(g) + H_2O(g) --\gt 2HNO_3(g) + NO(g)$
3. Balance the number of nitrogen and oxygen atoms, by putting a "3" as the coefficient of $NO_2$:
$3NO_2(g) + H_2O(g) --\gt 2HNO_3(g) + NO(g)$
- The equation is completely balanced.
