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What is the pH of a 0.300 M ammonia solution?
Please show detail.
1 Answer
- Steve OLv 71 decade agoFavorite Answer
NH3 in water <=> NH4+ & OH-
(0.300 Molar -x) <=> [X] & [X]
because the "X" is small, this simplifies to
NH3 in water <=> NH4+ & OH-
(0.300 Molar ) <=> [X] & [X]
Kbase = 1.78 e-5
from http://www.chemtutor.com/acid.htm#phst
Kb = [NH4+] [OH-] / [NH3}
1.78 e-5 = [X] [X] / [0.300]
X^2 = 5.34 e-6
X = [OH-] = 2.31 e-3
pOH = - log of 2.31 e-3
pOH = 2.636
since pH + pOH = 14
pH = 14 - 2.636
pH = 11.364
most people only have the Kb good to 2 sig figs
at which their answer would round off to
pH = 11.36
