1. Indicators Several chemicals change colour when they are placed in acidic or basic solutions These are called indicators because they indicate the pH of the substance. Some are natural (Red Cabbage) and some are synthetic (Bromothymol) Common indicators p. 270

2. Neutralization Reactions When an acid reacts with a base pH moves towards 7 Double displacement reactions – E.g. HCl (aq) + NaOH (aq)  HOH (l) + NaCl (aq) Produces a Salt and Water Acid + Base  Water + Salt

3. Neutralization Examples HCl + NaOH  H 2 O + NaCl H 2 SO 4 + 2KOH  2H 2 O + K 2 SO 4 Basically… H + + OH -  HOH = H 2 O The other portions of the acid and base join to make a salt.

4. What is a salt? A combination of positive and negative ions formed by the reaction of an acid and a base (ionic compound). Can re-hydrate (add water) to form an acid and a base.

5. Application of Neutralization Reactions Cleaning up chemical spills

6. Application Con’t Base + Acid  Water + Salt

7. Application - Heart Burn Heart Burn Video

8. Heart Burn Your stomach produces hydrochloric acid with a pH around 1.5 Some of the acid can escape up into your esophagus(where the food goes down) causing discomfort

9. Heart Burn Neutralization Reaction 2HCl (aq) + Mg(OH) 2(aq)  2H 2 O (l) + MgCl (s) Stomach Acid Antacid WaterSalt (HCl)(Base)