# Acids Lesson 14 Amphiprotic Ions Acids or Bases? Acids Lesson 14 Amphiprotic Ions Acids or Bases? Kwantlen Science Challenge: Kwantlen Science Challenge: Kwantlen Science Challenge: Amphiprotic Ions H3PO4 H2PO4HPO42PO43- Acid Amphiprotic Amphiprotic Base Amphiprotic ions have a Ka and a Kb. If the Ka > Kb, then the ion is an acid in water. If the Kb > Ka, then the ion is a base in water.

Is H2PO4- acid or basic acid 1. Is H2PO4- an acid or base when in water? Write the predominate hydrolysis equation for this ion. Ka (H2PO4-) = 6.2 x 10-8 Kb (H2PO4-) = Kw Ka(H3PO4) = 1 x 10-14 7.5 x 10-3

= 1.3 x 10-12 Ka > Kb Acid H2PO4- H2 O + HPO42 + H3 O+ Is HPO42- acid or basic basic 2.

Is HPO42- an acid or base when in water? Write the hydrolysis equation for this ion. Ka (HPO42-) = 2.2 x 10-13 Kb (HPO42-) = Kw Ka(H2PO4-) = 1 x 10-14 6.2 x 10-8 = 1.6 x 10-7 Kb > Ka HPO42-

+ base H2 O H2PO4- + OH- 3. Show by calculation if NH4F is an acid or base when in water. NH4F NH4+ + acid Both have weak parents- neither will cross off! What will the salt be?

Ka(NH4+) Kb (F-) = = = = = 5.6 x 10-10 Kw Ka(HF) 1 x 10-14 3.5 x 10-4 2.9 x 10-11 Ka > Kb acid Fbase 4. Show by calculation if NH4CH3COO is an acid or base when in water. NH4CH3COO

NH4+ acid + Ka(NH4+) = 5.6 x 10-10 Kb (CH3COO-) = = Kw Ka(CH3COOH) = 1 x 10-14 1.8 x 10-5 = 5.6 x 10-10

Ka = Kb CH3COObase neutral pH = 7.00 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH. 1H2CO3 ?L 0.100 M + 2KOH 0.0250 L 0.200 M K2CO3 + 2HOH 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH. 1H2CO3

?L 0.100 M 0.0250 L KOH + 2KOH 0.0250 L 0.200 M K2CO3 + 2HOH 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH. 1H2CO3 ?L 0.100 M + 0.0250 L KOH x 0.200 mol L 2KOH 0.0250 L

0.200 M K2CO3 + 2HOH 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH. 1H2CO3 ?L 0.100 M + 2KOH 0.0250 L 0.200 M K2CO3 + 2HOH 0.0250 L KOH x 0.200 mol x 1 mole H2CO3 L 2 mole KOH 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH.

1H2CO3 ?L 0.100 M + 2KOH 0.0250 L 0.200 M K2CO3 + 2HOH 0.0250 L KOH x 0.200 mol x 1 mole H2CO3 x 1 L L 2 mole KOH 0.100 mol 5. Calculate the volume of 0.100 M H2CO3 required to neutralize 25.0 mL of 0.200 M KOH. 1H2CO3 ?L 0.100 M +

2KOH 0.0250 L 0.200 M K2CO3 + 2HOH 0.0250 L KOH x 0.200 mol x 1 mole H2CO3 x 1 L = 0.0250 L L 2 mole KOH 0.100 mol 6. Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Mg(OH)2(s) Mg2+ + CN- + H2O

HCN + OH- NH4+ + H2O H3O+ + NH3 N2O4(g) 2NO2(g) 2H2O H3O+ +

OH- 2OH- 6. Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Ksp Mg(OH)2(s) Mg2+ + CN- + H2O HCN + OH-

NH4+ + H2O H3O+ + NH3 N2O4(g) 2NO2(g) 2H2O H3O+ + OH- 2OH- 6.

Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Ksp Mg(OH)2(s) Mg2+ + Kb CN- + H2O HCN + OH- NH4+ +

H2O H3O+ + NH3 N2O4(g) 2NO2(g) 2H2O H3O+ + OH- 2OH- 6. Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Ksp

Mg(OH)2(s) Mg2+ + Kb CN- + H2O HCN + OH- Ka NH4+ + H2O

H3O+ + NH3 N2O4(g) 2NO2(g) 2H2O H3O+ + OH- 2OH- 6. Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Ksp

Mg(OH)2(s) Mg2+ + Kb CN- + H2O HCN + OH- Ka NH4+ + H2O

H3O+ + NH3 Keq N2O4(g) 2NO2(g) 2H2O H3O+ + OH- 2OH- 6. Label the equation that has a Ka, Kb, Ksp, Kw, or Keq. Ksp

Mg(OH)2(s) Mg2+ + Kb CN- + H2O HCN + OH- Ka NH4+ + H2O

H3O+ + NH3 Keq N2O4(g) 2NO2(g) Kw 2H2O H3O+ + OH- 2OH-