Question

Write the overall, ionic and net ionic equations for the following reaction.
Hydroiodic acid (HI) and calcium hydroxide (Ca(OH)2)

Answer 1

This is an acid-base neutralization reaction. Does that help?

Answer 2

Not really. I don't quite understand how to do those things.

Answer 3

Well, in these reactions. The H+ from the acids and the OH- from the bases combine for the form water, H2O. H2O is a product of all acid-base neutralization reactions.

Answer 4

So, we have this as our shell:
HI (aq) + Ca(OH)2 (aq) --> H2O (l) + ?? (aq)

Answer 5

okay

Answer 6

However, we need to do something about the Ca and the I. After the reaction finishes, the Ca and I create calcium iodide. What is the formula for calcium iodide?

Answer 7

This is an ionic compound. So, calcium has a 2+ charge and iodine has a -1 charge.

Answer 8

Cal2

Answer 9

Good. So now the shell of the equation looks like this:
HI (aq) + Ca(OH)2 (aq) ---> H2O (l) + CaI2 (aq)

Labeling each substance as "aqueous" or "liquid" helps in the next part.
However, for now, we need to balance this equation.

Answer 10

okay

Answer 11

The balanced equation will give us the first part: the overall equation.

Answer 12

how do you balance it?

Answer 13

Oh, lol. We have to match up the same number of moles (or atoms) of each element on both the left and right side.
For example, there are 2 I's on the right side (b/c of the CaI2), but only one I on the right side, in the HI.

Answer 14

so you have to add to the sides to make them equal?

Answer 15

No. when balancing equations, you want to simply add coefficients to the front of a substance that needs to have more elements. Go back to our iodine example: