How Do You Balance Zinc and Nitrate in a Basic Solution?

[KingNothing]

I don't understand this question in my chemistry book. It's not homework, I'm just studying, but I would really like to know.

What are the coefficients in front of nitrate ion and zinc when the following equation is balanced in a basic solution:

___ NO3-(aq) + ___ Zn(s) --> ___ Zn2+(aq) + ___ NO(g)?

1) 2, 5
2) 2, 3
3) 3, 4
4) 3, 2

That's the nitrate ion, zinc, zinc with a 2+ charge, and NO. Can someone explain how to do this? Also, what is the answer, so I can work backwards?

So far, it looks to me like both reactants are being oxidised, so I'm left with a big half-reaction with electrons.

 

[KingNothing]

Alright, I finally got it! As it turns out, my error the whole time was labeling H as a negative ion in my reduction reaction.

 

[Blueshift5]

A half-reaction in chemistry is a representation of either the oxidation or reduction process that occurs in a chemical reaction. In this case, the half-reaction being referred to is the oxidation of zinc to zinc ions.

To balance the given equation in a basic solution, you must first identify the atoms that are being oxidized and reduced. In this case, zinc is being oxidized and nitrate ion is being reduced.

To balance the atoms in the half-reaction, you must add the appropriate coefficients in front of each species. In this case, the coefficients in front of nitrate ion and zinc are 2 and 5, respectively.

The balanced half-reaction would be: 2NO3-(aq) + 5Zn(s) --> 5Zn2+(aq) + 2NO(g)

To balance the overall equation, you must also add the same number of electrons to both sides of the equation. In this case, 10 electrons are added to the left side to balance the charge. The final balanced equation in basic solution is:

2NO3-(aq) + 5Zn(s) + 10OH-(aq) --> 5Zn2+(aq) + 2NO(g) + 5H2O(l)

The answer to the question would be option 1) 2, 5. Working backwards, you can see that the coefficients in front of nitrate ion and zinc are 2 and 5, respectively, when the equation is balanced in a basic solution.

I hope this explanation helps you understand the concept of half-reactions and how to balance equations in basic solution. Remember to always identify the atoms being oxidized and reduced and add the appropriate coefficients to balance the atoms and charge.