ACIDS AND BASES Chemistry

Arrhenius Acids & Bases  Arrhenius Acids  Donate H + to the solution  HNO 3 H + + NO 3 -  Arrhenius Bases  Donate OH - to the solution  NaOH Na + + OH - H2OH2O H2OH2O

Brønsted-Lowry Theory  Acid: proton (H + ) donor  HCl  H 2 SO 4  Base: proton (H + ) acceptor  NaOH  NH 3

Questions… 1. Which can be a B-L acid? a) HNO 3 b) Cu 2+ c) HCO Which can be a B-L base? a) OH - b) H 2 O c) HCO 3 -

Conjugate Pairs  All B-L acid/base reactions have the following set-up: HA + B ⇌ A - + HB +  Conjugate Pairs:  HA & A -  B & HB + Conjugate Pair 3

Conjugate Acid/Base Pair Examples Some Conjugate Acid-Base Pairs AcidBase HClCl – H 2 SO 4 HSO 4 – H3O+H3O+ H2OH2O SO 4 2– CH 3 COOHCH 3 COO – H 2 CO 3 HCO 3 − HCO 3 – CO 3 2– NH 4 + NH 3 H2OH2OOH –

Conjugate Acids & Bases Practice 1. Determine the conjugate acids for the following: 1. CN - 2. H 2 PO PO H 2 O 5. NH 3  Determine the conjugate bases for the following: a. H 3 O + b. H 2 PO 4 - c. H 3 PO 4 d. HBr e. H 2 SO 4

Predict the following: 1. HNO 3 + NH 3  2. NH PO 4 3-  3. H 3 O + + CO 3 2-  4. CH 3 COOH + H 2 O 

Lewis’s Definition of Acids & Bases  Defines acids/bases in terms of e - pairs  Lewis Acid:  e - pair acceptor  Lewis Base:  e - pair donor

Lewis Acids & Bases  Lewis Acid:  Must be able to accept lone e - pairs (incomplete octet)  B, Be, Transition Metals  Lewis Base:  Must have lone e - pairs  Dative bond:  Shown with arrows to indicate donation of e - pairs

Complex Ions  Lewis acids will often form complex ions  Attached bases are called ligands

Acid/Base Definition Summary Acid-Base Definitions TypeAcidBase ArrheniusH + producerOH – producer Brønsted-LowryH + donorH + acceptor Lewiselectron-pair acceptorelectron-pair donor