[kaywalker]

I know what the answer is. please read below what my real question is. How many drops of 12 M HCl would you add to 1 L of 0.1 M HC2H3O2 to make [C2H3O2]= 1 * 10 ^ -4 M? Assume that 1 drop is 0.05 mL and the volume of solution remains 1 L ater the 12 M HCl is diluted.

the answer is 27.4=28 drops. But here's my question, if we add H3O ions to the solution wouldn't this push the reaction in the reverse order? here we are treating it as if concentration of HC2H3O2 remain constant, but in reality it increases. why is that?

What I'm asking is how should we account for the increase in C2H3O2 concentration when we are doing the final calculation to find the amount of H3O that should be added?

thanks in advance.

[Borek]

Put charges on ions, question is hard to understand now.

Write reaction equation of acetic acid dissociation.

here's my question, if we add H3O ions to the solution wouldn't this push the reaction in the reverse order? here we are treating it as if concentration of HC2H3O2 remain constant, but in reality it increases. why is that?

What I'm asking is how should we account for the increase in C2H3O2 concentration when we are doing the final calculation to find the amount of H3O that should be added?

Honestly, I have no idea what you are asking about, which most likely means you are doing some very basic mistake which makes you reasoning completely off. That's probably why nobody answered yet.

Please try to describe what you mean once again, using other words, or better yet - try to show how you would calculate the answer, it will be easier to spot the problem.

[AWK]

The problem concerns a common ion effect on dissociation of acetic acid.
K=[H3O+][CH3COO-]/[CH3COOH]
You need K form tables.
Calculate concentration of H3O+ assuming all H3O+ comes from HCl and [CH3COOH]=0.1

Note answer and your data contradict concerning significant digits