Kb NH4 OH

1
CH 17 42 weak base titration
CH 17 42 a weak base ionization in pure
water. H20 NH3 ?? NH4 OH-
THIS IS BEFORE THE TITRATION, NO H ADDED YET.
Kb NH4OH- NH3
1.8 10-5 XX 0.030-X
1.8 10-5 XX 0.030
X 7.348 10-4 OH- pOH- 3.14 pH 10.86
2
CH 17 42 b weak base TITRATION AFTER 0.010 L OF
H IS ADDED TO THE BASE SOLUTION IN PART b.
H ADDED 0.0250 M 0.0100L 2.5 10-4 mol
NH3 INITIAL 0.030 M ( 9.0 10-4 MOLE)
Kb NH4OH- NH3
NEUTRAIZATION STOICHIOMETRY (MOLES)
2.510-4 MOL /0.040L6.2510-3 MOLAR
1.8 10-5 6.2510-3X
0.01625
X 4.610-5 MOLAR pH 9.66
6.510-4/0.040L 0.01625
3
CH 17 42 c weak base TITRATION AFTER 0.020 L OF
H IS ADDED TO THE BASE SOLUTION IN PART c.
H ADDED 0.0250 M 0.0200L 5.0 10-4
mol NH3 INITIAL 0.030 M ( 9.0 10-4 MOLE)
Kb NH4OH- NH3
NEUTRAIZATION STOICHIOMETRY (MOLES)
5.010-4 MOL /0.050L0.010 MOLAR
1.8 10-5 0.010X
0.008
OH- X 1.4410-5 MOLAR pH 9.19
4.010-4/0.050L 0.008M
4
CH 17 42 d weak base TITRATION AFTER 0.0350 L
OF H IS ADDED TO THE BASE SOLUTION IN PART d.
H ADDED 0.0250 M 0.0350L 8.75 10-4
mol NH3 INITIAL 0.030 M ( 9.0 10-4 MOLE)
Kb NH4OH- NH3
NEUTRAIZATION STOICHIOMETRY (MOLES)
8.7510-4 MOL /0.065L0.01346 MOLAR
1.8 10-5 0.01346X
4.010-4
OH- X 5.34910-7 MOLAR pH 7.73
0.2510-4/0.065L 4.010-4M
5
CH 17 42 e weak base TITRATION AFTER 0.0360 L
OF H IS ADDED TO THE BASE SOLUTION IN PART e.
H ADDED 0.0250 M 0.0360L 9.0 10-4
MOLE NH3 INITIAL 0.030 M ( 9.0 10-4 MOLE)
? NOTE THE MOLES OF H ADDED THE MOLES OF BASE
INITIAL, YOU ARE AT EQUIVALENCE!
NEUTRAIZATION STOICHIOMETRY (MOLES)
WILL NOW UNDERGO HYDROLYSIS
6
CH 17 42 e(continued) weak base TITRATION AT
EQUIVALANCE. H2O NH4 ?? NH3 H
Ka NH3H NH4
5.5610-10 XX
9.010-4mol/0.660 L
5.5610-10 XX .01364
M
X 2.75 10-10 M H pH 5.56