Acids and Alkalis
pH scale
- 0- 14 : Acids – 0-6 Neutral – 7 Alkalis – 8-14
Universal indicator
- Red to yellow is acid green is neutral blue to purple is alkali
Acids and alkalis neutralise each other
- Acid (pH less than 7) in water creates H+ ions
- A base (pH greater than 7)
- An alkali is a base that can dissolve in water to create OH- ions
- Acid + base = salt + water which in ion terms is: H+ + OH- = H2O
- Acid + base/ alkali neutralises (to make water
State symbols tell you the physical state of the substance
- (s) is a solid
- (l) is a liquid
- (g) is a gas
- (aq) is aqueous – means dissolved in water
Acids and metal
- Acid + metal = salt + hydrogen
- The more reactive the metal the faster the reaction it will and the more explosive
- E.g. sodium very explosive – magnesium has a big pop – aluminium – zinc – iron – copper (doesn’t react at all with dilute acid so no pop)
- The pop is when you test for hydrogen
- Hydrochloric acid would produce chlorides
- Sulphuric acid would produce sulphates
- Nitric acid produces nitrates