1. Bronsted – Lowrey theory Essentially this theory is quite simple :- An acid will DONATE a proton H + A base will ACCEPT a proton H + Example C 6 H 5 COO - + H 2 O C 6 H 5 COOH + OH - The H 2 O acts as an acid as it donates the proton and the C 6 H 5 COO - as the base as it accepts it

2. Problems 1. NH 3 + H 2 O NH 4 + + OH - Explain why ammonia is acting as a base in the above equation. Answer The ammonia has a “lone pair” of electrons which accepts the H + from the water molecule (acting as an acid) i.e. NH 3 + H + NH 4 +

3. Problems (continued) 2. CH 3 COOH + OH - CH 3 COO - + H 2 O On the left hand side of the equation state with an explanation what is acting as a base. Answer The OH - is acting as the base as it accepts the H + from the ethanoic acid. i.e. OH - + H + H 2 O

4. Problems (continued) 3. H 2 O(1) + H 2 O(2) H 3 O + + OH - State with an explanation which water molecule acts as a base and an acid. Answer (1) acts as a base as it accepts the H + (2) acts as an acid as it donates the H +

5. Problems (continued) 4. HCO 3 - + OH - CO 3 2- + H 2 O On the right hand side of the equation, explain what is acting as an acid. Answer The H 2 O is acting as the acid as it donates a H + to the CO 3 2- producing the hydrogen carbonate HCO 3 -