1. Acids and alkalis Solutions can be sorted by whether they are: acid, alkali or neutral. When a substance dissolves in water it makes a solution.

2. When the oxide of some non-metals dissolve in water they make an acid. Acids have a sour taste. They are corrosive.

3. Acids Lemon juice contains citric acid, and vinegar contains ethanoic acid. Some strong acids are hydrochloric acid, sulphuric acid and nitric acid. Some weak acids are ethanoic acid, citric acid and carbonic acid. There are many acids present in our everyday lives.

4. Alkalis a.k.a. BASES When the oxides of some metals dissolve in water they make an alkali solution. Alkalis react with acids and neutralize them. neutralize Many everyday substances are alkalis. They feel soapy. They are corrosive.

5. Alkalis Alkalis are present in many cleaning substances in use in our homes. Kitchen cleaners are alkaline because they contain ammonia or sodium hydroxide, which attack grease. Calcium hydroxide and sodium hydroxide are strong alkalis. The most recognisable and common weak alkali is ammonia.

6. ACIDS tend to begin with H +, while BASES tend to END with OH - ACIDS HCl = hydrochloric acid H 2 SO 4 = sulfuric acid HNO 3 = nitric acid BASES *Ca(OH) 2 =calcium hydroxide *NaOH = sodium hydroxide *LiOH = lithium hydroxide **NH 3 = ammonium **CaCO 3 = calcium carbonate (two bases not ending in OH-)

7. characteristics of ACIDS & BASES ACIDS taste SOUR are corrosive to metals change litmus RED become less acidic when mixed with bases. bases BASES Feel SLIPPERY change litmus BLUE become less basic when mixed with acids. acids

8. Indicators They change colour in acid or alkaline solutions. Different indicators change to different colours. Indicators help you find out whether a solution is acidic or not.

9. Litmus Test Litmus is an indicator. It changes colour in acid and alkaline solutions. Litmus is red in an acid. Litmus is blue in an alkali.

10. Universal Indicator Universal indicator changes colour in acids and alkalis. Its colour shows the strength of an acid or alkali. ACIDSALKALIS Neutral

11. The pH scale 1 – 6 8 - 14 Alkalis 7 Neutral Acids H + = OH - more OH - more H+

12. Neutralization Acids and alkalis react with each other. The alkali cancels out the acid in the reaction. This is called neutralization. WATER & A salt is made.salt