1. They are solutions of compounds in water. Acids are liquids
2. If concentrated they can be corrosive.
3. Turn blue litmus paper red - this is an easy test for an acid!
4. Usually react with metals to form salts. Acids are sour!
5. Acids release hydrogen ions, H+ in solution.
6. Turn Universal Indicator from green to red, and have a pH less than 7.
Examples of acids: are vinegar (ethanoic acid) and lemon juice (citric acid)
magnesium + hydrochloric acid -> magnesium chloride + hydrogen gas
1. Hydrochloric acid, HCl(aq)
2. Nitric acid, HNO3(aq)
3. Sulphuric acid, H2SO4(aq)
4. Phosphoric Acid, H3PO4
1. They feel soapy to touch.
2. They are soluble bases.
3. Like acids, they can burn the skin.
4. They turn red litmus blue - this is how you test for an alkali!
5. Alkalis contain hydroxide ions (OH-).
6. They taste bitter.
7. Turns Universal Indicator from green to blue or purple.
Some common alkalis used in your laboratories at school will be:
1. Sodium hydroxide, NaOH(aq)
2. Ammonia, NH3NH4OH(aq)
3. Calcium hydroxide, Ca(OH)2(aq)
1. Litmus paper is not affected by neutral paper.
2. Tend to be harmless
3. Universal Indicator stays green.
Common examples of neutral substances:
2. Sodium chloride solution, NaCl(aq)(common salt)
3. Sugar solution C6H12O6(aq)
Acid + Alkali -> Salt +Water
Acid + Metal-> Salt +Hydrogen
Acid + Carbonate-> Salt +Water +Carbon Dioxide
Acid + Metal Oxide-> Salt +Water
Acid + Hydroxide-> Salt +Water