Write a balanced chemical equation to show the reaction that occurs when each weak acid reacts with water. (Omit states-of-matter from your answer. Use the lowest possible whole number coefficients.)
(b) HCHO2
I've gotten a and c correct, and from that I know that WebAssign wants the reactants to be HCHO2 and H2O. I think that H3O should be a product, but I'm not quite sure. What's causing me trouble is the carbon - I don't know how that fits into the products.
HCHO2 probably is formic acid. It might be easier for you to see if it was written as HCOOH. It's the H on the right hand side that is the acidic hydrogen and if you look at it that way you would write HCOOH + H2O => H3O^+ + HCOO^-. Often these are written with that acidic H placed first as in HCHO2 and I expect that is what webassign wants.
HCHO2 + H2O ==> H3O^+ + CHO2^-
Thanks. How do I know if a substance is formic acid?
Actually, you don't but if the empirical formula is HCHO2 or CH2O2 and the Lewis structure looks like HCOOH it's a good bet it is formic acid. That's why they write the abbreviated formula as HCHO2 and that USUALLY means the first H written is the one that ionizes and the other H atoms listed are not involved in dissociation.
To write a balanced chemical equation for the reaction of a weak acid with water, you need to first identify the dissociation of the weak acid in water. Weak acids partially dissociate, meaning they release some of their protons (H+) into the solution.
For the weak acid HCHO2 (formic acid), the dissociation in water can be represented as follows:
HCHO2 + H2O --> H3O+ + CHO2-
In this equation, the water molecule acts as the base, accepting a proton (H+) from the weak acid to form a hydronium ion (H3O+). The remaining part of the weak acid, CHO2-, is the conjugate base.
The carbon atom remains in the formate ion (CHO2-), which is the conjugate base of formic acid. The carbon does not undergo any significant changes or conversions during the reaction.
So to summarize, the balanced chemical equation for the reaction between HCHO2 and water is:
HCHO2 + H2O --> H3O+ + CHO2-