Answer:
11. Conjugate base
12. Acid
13. Acid
14. Conjugate base
15. Acid
16. Base
17. Conjugate acid
18. Acid
19. Conjugate base
20. Neutral
Step-by-step explanation:
Determine the reactions of each in water. Remember that:
Acid → Releases a proton ⇒ Conjugate base
Base → Accept a proton ⇒ Conjugate acid
CN⁻ + H₂O ⇄ HCN + OH⁻
Cianide ion comes from cianhydric acid. Therefore it is the conjugate base
H₃PO₄ + H₂O ⇄ H₃O⁺ + H₂PO₄⁻
Phosphoric acid it is a polyprotic acid and It can release, at least 3 protons.
All the products are the conjugate bases (H₂PO₄⁻, HPO₄⁻², PO₄⁻³)
HCl, the same case as H₃PO₄. It is an acid that release a proton.
HCl + H₂O ⇄ H₃O⁺ + Cl⁻
The conjugate base will be the chloride formed
ClO₂⁻ + H₂O ⇄ HClO₂ + OH⁻
Same case as the cyanide. The chlorite anion takes a proton from water to become, chlorous acid (the conjugate acid)
H₂SO₄ is an acid. It is a diprotic acid, because it can release 2 protons:
H₂SO₄ + H₂O → HSO₄⁻ + H₃O⁺
The products HSO₄⁻ and SO₄⁻² are the conjugate base
NaOH is a base. In water dissociates, as this equation shows:
NaOH → Na⁺ + OH⁻
NH₄⁺ comes from the ammonia. Ammonia is the base, so the ammonium is the conjugate acid.
NH₄⁺ + H₂O ⇄ NH₃ + OH⁻
HNO₃ is an acid. The nitrate will be the conjugate base.
HNO₃ + H₂O → NO₃⁻ + H₃O⁺
F⁻ is the fluoride anion. It comes from the fluorhydric acid.
That's why it is the conjugate base: F⁻ + H₂O ⇄ HF + OH⁻
Distilled water is always neutral. It can behave as an acid and a base. This is called an amphoteric compound.