Question

Consider the ionization constants
cyanic acid (HOCN) : Ka= 3.5×10−4; ammonia (NH3): Kb= 1.8×10−5. A solution
of ammonium cyanate (NH4OCN) is
1. acidic, because the cation and the anion hydrolyze to the same extent.
2. acidic, because the anion hydrolyzes to a greater extent than the cation.
3. basic, because the cation hydrolyzes to a greater extent than the anion.
4. basic, because the anion hydrolyzes to a greater extent than the cation.
5. neutral, because the cation hydrolyzes to a greater extent than the anion.
6. neutral, because the anion hydrolyzes to a greater extent than the cation.
7. neutral, because NH4OCN is a weak
base/weak acid salt.
8. basic, because the cation and the anion hydrolyze to the same extent.
9. acidic, because the cation hydrolyzes to a greater extent than the anion.
10. neutral, because the cation and the anion hydrolyze to the same extent.

Answer 1

(H^+) for a salt of a weak acid and a weak base = sqrt(KwKa/Kb). Solve for (H^+) and you have your answer.

Answer 2

acidic, because the cation hydrolyzes to a
greater extent than the anion.

Answer 3

Michael is correct. I tried it.