1. REVISION ACIDS & BASES

2. MODELS ARRHENIUS THEORY A n acid is a substance that produces hydrogen ions (H + )/hydronium ions (H 3 O + ) when it dissolves in water. A base is a substance that produces hydroxide ions (OH - ) when it dissolves in water. LOWRY-BRØNSTED THEORY An acid is a proton (H + ion) donor. A base is a proton (H + ion) acceptor

3. ACIDS STRONG ACIDS ionise completely in water to form a high concentration of H3O+ ions. Examples of strong acids are hydrochloric acid, sulphuric acid and nitric acid. WEAK ACIDS ionise incompletely in water to form a low concentration of H 3 O + ions. Examples of weak acids are ethanoic acid and oxalic acid. POLYPROTIC ACIDS Acids that can donate more than one proton AMPHOLYTE Can be an acid OR a base

4. BASES STRONG BASES dissociate completely in water to form a high concentration of OH- ions. Examples of strong bases are sodium hydroxide and potassium hydroxide WEAK BASES dissociate/ionise incompletely in water to form a low concentration of OH ions. Examples of weak bases are ammonia, calcium carbonate, potassium carbonate, calcium carbonate and sodium hydrogen carbonate.

5. CONCENTRATED AND DILUTE CONCENTRATED ACIDS/BASES contain a large amount (number of moles) of acid/base in proportion to the volume of water. DILUTE ACIDS/BASES contain a small amount (number of moles) of acid/base in proportion to the volume of water

6. CONCENTRATED AND DILUTE

7. IONISATION HCℓ(g)+H 2 O(ℓ) →H 3 O + (aq) + Cℓ - (aq) NH 3 (g) + H 2 O(ℓ) → NH + 4 (aq)+ OH - (aq) H 2 SO 4 (aq) + 2H 2 O(ℓ) →2H 3 O + (aq) +SO 2 4− (aq)

8. CONJUGATE ACID-BASE PAIRS HCℓ(g)+H 2 O(ℓ) →H 3 O + (aq) + Cℓ - (aq) NH 3 (g) + H 2 O(ℓ) → NH + 4 (aq)+ OH - (aq) H 2 SO 4 (aq) + 2H 2 O(ℓ) →2H 3 O + (aq) +SO 2 4− (aq)

9. NEUTRALISATION REACTIONS HCℓ(aq)+NaOH(aq)→NaCℓ(aq)+ H 2 O(ℓ) HCℓ(aq)+KOH(aq)→KCℓ(aq)+ H 2 O(ℓ) HCℓ(aq)+Na 2 CO 3 (aq)→NaCℓ(aq) +H 2 O(ℓ) + CO 2 (g) HNO 3 (aq) +NaOH(aq)→NaNO 3 (aq) +H 2 O(ℓ) H 2 SO 4 (aq) +2NaOH(aq)→Na 2 SO 4 (aq) +2H 2 O(ℓ) (COOH) 2 (aq) +NaOH(aq)→(COO) 2 Na 2 (aq)+ H 2 O(ℓ) CH 3 COOH(aq) + NaOH(aq) → CH 3 COONa(aq) + H 2 O(ℓ)

10. HYDROLYSIS & NEUTRALISATION HYDROLYSIS as the reaction of a salt with water Hydrolysis of the salt of a weak acid and a strong base results in an alkaline solution, i.e. the pH > 7. Examples of such salts are sodium ethanoate, sodium oxalate and sodium carbonate. O Hydrolysis of the salt of a strong acid and a weak base results in an acidic solution, i.e. the pH < 7. An example of such a salt is ammonium chloride. The salt of a strong acid and a strong bases does not undergo hydrolysis and the solution of the salt will be neutral, i.e. pH = 7.

11. PHENOLPHTHALEIN STRONG BASE WITH WEAK ACID STRONG BASE WITH STRONG ACID

12. BROMOTHYMOL STRONG BASE WITH STRONG ACID

13. METHYL ORANGE WEAK BASE WITH STRONG ACID

14. TITRATION EQUIVALENCE POINT of a titration is the point at which the acid /base has completely reacted with the base/acid. ENDPOINT of a titration is the point where the indicator changes colour.

15. EXPERIMENT OXALIC ACID WITH SODIUM HYDROXIDE List the apparatus needed or identify the apparatus from a diagram. Describe the procedure to prepare a standard oxalic acid solution. Describe the procedure to conduct the titration. Describe safety precautions. o Describe measures that need to be in place to ensure reliable results. Interpret given results to determine the unknown concentration.

16. pH values of strong acids&bases pH = -log[H 3 O + ] Kw as the equilibrium constant for the ionisation of water or the ionic product of water or the ionisation constant of water K w = [H 3 O + ][OH - ] = 1 x 10 14 at 298 K auto-ionisation of water, i.e. the reaction of water with itself to form H 3 O + ions and OH - ions

17. pH values of strong acids&bases

18. Concentration from pH