Balance the chemical equation : Zn + HNO3 → Zn(NO3)2 + NO + H2O. ( some of you think this is wrong ,no it is true.
Answers
If the following reaction can take place, then the balanced chemical equation will be given as:
3 Zn + 8 HNO3 → 3 Zn(NO3)2 + 2 NO + 4 H2O
- The product of oxidation is dependent upon the concentration, temp and nature of the acid.
- That is why metal zinc on reaction with concentrated HNO3 gives N2O and on reaction with dilute HNO3 gives NO2.
- So, the above reaction can take place only at certain specified conditions.
- If it occurs, the balanced reaction of zinc with HNO3 to give NO is given above.
Given : skeleton chemical equation is ...
Zn + HNO₃ ⇒Zn(NO₃)₂ + NO + H₂O
To write : Balanced chemical equation.
solution : let's solve it by using electron - ion method.
in this method, first balance central atom, then
to balance oxygen atom, add water molecule.
to balance oxygen atom, add water molecule. to balance hydrogen atom, add hydrogen ions
to balance oxygen atom, add water molecule. to balance hydrogen atom, add hydrogen ions finally balance ions by adding electrons.
step 1 : HNO₃ + 3H⁺ + 3e¯⇔NO + 2H₂O .....(1)
step 2 : Zn + 2HNO₃ ⇔Zn²⁺ + 2H⁺ + 2NO₃¯ + 2e¯ ........(2)
multiplying 3with equation (2) and 2 with equation (1) and then adding both of these,
2HNO₃ + 6H⁺ + 6e¯⇔2NO + 4H₂O
3Zn + 6HNO₃ ⇔3Zn²⁺ + 6H⁺ + 6NO₃¯ + 6e¯
.....................................................................................
8HNO₃ + 3Zn ⇔2NO + 3Zn²⁺ + 4H₂O + 6NO₃¯
3Zn + 8HNO₃ ⇔3Zn(NO₃)₂ + 2NO + 4H₂O
Therefore balanced chemical equation is 3Zn + 8HNO₃ ⇔3Zn(NO₃)₂ + 2NO + 4H₂O