Homework Assignment #19

Complete and balance the following Brønsted-Lowry acid-base reactions and find the value for Kc for the reaction.

0) NH3(aq) + HCN(aq)

1) NH3(aq) + HOCN(aq)

2) NH3(aq) + HF(aq)

3) NH3(aq) + HOCl(aq)

4) NH3(aq) + HNO2(aq)

5) N2H4(aq) + CH3CO2H(aq)

6) N2H4(aq) + HClO2(aq)

7) N2H4(aq) + HOI(aq)

8) N2H4(aq) + HIO3(aq)

9) N2H4(aq) + HN3(aq)

Answer

Complete and balance the following Brønsted-Lowry acid-base reactions and find the value for Kc for the reaction.

0) NH3(aq) + HCN(aq)

NH3(aq) + HCN(aq) NH4+(aq) + CN(aq)

Kc = Ka(HCN)/Ka(NH4+) = (6.2×10–10)/(5.6×10–10) = 1.1

1) NH3(aq) + HOCN(aq)

NH3(aq) + HOCN(aq) → NH4+(aq) + OCN(aq)

Kc = Ka(HOCN)/Ka(NH4+) = (3.5×10–4)/(5.6×10–10) = 6.3×105

2) NH3(aq) + HF(aq)

NH3(aq) + HF(aq) → NH4+(aq) + F(aq)

Kc = Ka(HF)/Ka(NH4+) = (6.6×10–4)/(5.6×10–10) = 1.2×106

3) NH3(aq) + HOCl(aq)

NH3(aq) + HOCl(aq) NH4+(aq) + OCl(aq)

Kc = Ka(HOCl)/Ka(NH4+) = (2.9×10–8)/(5.6×10–10) = 52

4) NH3(aq) + HNO2(aq)

NH3(aq) + HNO2(aq) → NH4+(aq) + NO2(aq)

Kc = Ka(HNO2)/Ka(NH4+) = (7.2×10–4)/(5.6×10–10) = 1.3×106

5) N2H4(aq) + CH3CO2H(aq)

N2H4(aq) + CH3CO2H(aq) → N2H5+(aq) + CH3CO2(aq)

Kc = Ka(CH3CO2H)/Ka(N2H5+) = (1.8×10–5)/(1.2×10–8) = 1.5×103

6) N2H4(aq) + HClO2(aq)

N2H4(aq) + HClO2(aq) → N2H5+(aq) + ClO2(aq)

Kc = Ka(HClO2)/Ka(N2H5+) = (1.1×10–2)/(1.2×10–8) = 9.2×105

7) N2H4(aq) + HOI(aq)

N2H4(aq) + HOI(aq) N2H5+(aq) + OI(aq)

Kc = Ka(HOI)/Ka(N2H5+) = (2.3×10–11)/(1.2×10–8) = 1.9×10–3

8) N2H4(aq) + HIO3(aq)

N2H4(aq) + HIO3(aq) → N2H5+(aq) + IO3(aq)

Kc = Ka(HIO3)/Ka(N2H5+) = (1.6×10–1)/(1.2×10–8) = 1.3×107

9) N2H4(aq) + HN3(aq)

N2H4(aq) + HN3(aq) → N2H5+(aq) + N3(aq)

Kc = Ka(HN3)/Ka(N2H5+) = (1.9×10–5)/(1.2×10–8) = 1.6×103