Zn (neutral) + HNO3 -> NH4+ + Zn2+

Question

balance redox pls help thanks

Answer 1

Oh, redox reactions can look very scary, but in reality they can be readily conquered.

 

Step one: determine the oxidation numbers of the elements to see which is oxidized and which is reduced.

Zn goes from 0 to +2

N goes from +5 to -3

 

Step two: split the given reaction into the two half reactions

 

Zn → Zn²⁺ (oxidation)

HNO₃ → NH₄⁺ (reduction)

 

Step three: balance each half reaction by adding oxygen atoms as water molecules

 

HNO₃ → NH₄⁺ + 3 H₂O

 

Then balance hydrogen atoms by adding H⁺

 

9 H⁺ + HNO₃ → NH₄⁺ + 3 H₂O

 

Now, balance charges by adding electrons

 

Zn → Zn²⁺ + 2e^-

8 e^- + 9 H⁺ + HNO₃ → NH₄⁺ + 3 H₂O

 

Final steps are to multiply the half reactions by the proper coefficients to get the electrons to cancel, add the half reactions, and eliminate any substances that are the same on both sides of the reaction.

 

Jim S.