NH 4 aq H aq NH 3 aq pH p K a log NH 3 NH 4 p K a 925 pH 925 log 030 036 917

Nh 4 aq h aq nh 3 aq ph p k a log nh 3 nh 4 p k a 925

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NH 4 + ( aq ) H + ( aq ) + NH 3 ( aq ) pH = p K a + log [NH 3 ] [NH 4 + ] p K a = 9.25 pH = 9.25 + log [0.30] [0.36] = 9.17 = 9.20 NH 4 + ( aq ) + OH - ( aq ) H 2 O ( l ) + NH 3 ( aq ) start (moles) end (moles) 0.029 0.001 0.024 0.028 0.0 0.025 pH = 9.25 + log [0.25] [0.28] [NH 4 + ] = 0.028 0.10 final volume = 80.0 mL + 20.0 mL = 100 mL [NH 3 ] = 0.025 0.10 16.3 Chemistry In Action: Maintaining the pH of Blood 16.3 Acid-Base Indicators HIn ( aq ) H + ( aq ) + In - ( aq ) 10 [HIn] [In - ] Color of acid (HIn) predominates 10 [HIn] [In - ] Color of conjugate base (In - ) predominates 16.5 pH 16.5
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