Acetic acid has a Ka = 1.75 x 10-5 and formic acid has a Ka = 1.8 x 10-4. Which is the stronger acid?
You COULD go through the math and calculate the H^+ of each and the larger H^+ would be the stronger. However, you should be able to reason it through without the math.
........HAc ==> H^+ + Ac^-
1.75E-5 = (H^+)(Ac^-)/(HAc)
.........Hform ==> H^+ + form^-
1.8E-4 = (H^+)(form^-)/(Hform)
Which is the larger Ka? Hform of course. Larger Ka expression means products are larger than reactants. So larger Ka has larger H^+. Which is stronger?
To determine which is the stronger acid, we need to compare their acid dissociation constants (Ka) values. The higher the value of Ka, the stronger the acid.
From the given data:
Acetic acid: Ka = 1.75 x 10^-5
Formic acid: Ka = 1.8 x 10^-4
Comparing the two, we can observe that formic acid has a higher Ka value (1.8 x 10^-4), while acetic acid has a lower Ka value (1.75 x 10^-5).
Therefore, formic acid is the stronger acid because it has a higher Ka value than acetic acid.