Properties of acids

• Acid: any substance that releases hydrogen ions, H+, in aqueous solution

  • Aqueous solutions of acids are electrolytes,

• Acids have a sour taste

  • Example: Lemons, vinegar, and sour candies all contain acids.

• Acids change the color of certain acid-base indicates.

• Acids react with active metals to yield hydrogen gas.

• Acids react with bases to produce a salt compound and water.

• Turn blue litmus red

• Turn methyl orange red

• Turns Phenolphthalein colourless

• TiUniversal indicator Red /orange

• Contains PH-level below 7

Organic acid

• Organic Acid : found in natural products such as plants and animals.

  • They are sour to taste.

  • These acids are relatively harmless.( For example), they are not corrosive etc.

  • Example of some common organic acids: Ethanoic acid, citric acid, lactic acid.

Inorganic acid

• Inorganic acids: are corrosive, they have a sour taste and turn blue litmus red.

  • Hydrochloric acid

  • Sulphuric acid

  • Nitric acid

Weak and strong acid

• Strong acid which is completely ionized in an aqueous solution.

  • Eg: Hydrogen chloride (HCl), sulphuric acid, nitric acid.

• Weak acid which partially ionises in an acquous solution.

• Eg:carbonic, ethanoic , sulphurous, citric , carbonic.

Bases

• Bases: form a class of chemical substances which include all metal oxides and hydroxides.

  • A soluble base is called an 'alkali' an in aqueous solution, it produces hydroxide ion (OH-)

Properties of Bases

• Proton acceptors

  • as they contain hydroxide ions

• PH greater than 7

• Bitter taste

• Bases effect indicators

• Turn red litmus Blue

• Phenolphthalein turns purple/pink

• Universal indicator Blue

• Methyl orange YELLOW

• Slippery solutions

• Bases neutralise acids

• React with acids to form salt and water

• Examples of bases: Sodium hydroxide, potassium hydroxide, acqeuous ammonia, calcium hydroxide, magnesium oxide, copper (II) oxide.

Reactions

• Metal and acid➡️ salt and hydrogen

• Eg: zinc + sulphuric acid➡️ zinc sulphate+ Hydrogen

• Metal oxide + acid ➡️ salt and water

• Eg: Copper(II) oxide + sulphuric acid➡️ copper sulphate+ water

• Metal hydroxide + acid ➡️salt and water

• Eg: Potassium hydroxide+ hydrochloric acid ➡️ potassium chloride + water

• Metal carbonate + acid ➡️salt+water+ carbon dioxide

• Eg: Zinc carbonate+ nitric acid ➡️ zinc nitrate +water+ carbon dioxide

Oxides

• Basic oxides :solid metal oxides, some of which dissolve in water to form alkalis

• Acidic oxides :non-metal oxides, which dissolve in water to form acids

• Neutral oxides :non-metal oxides which are usually insoluble in water and have neither acidic nor basic properties

• Amphoteric oxides : metal oxides which can react with both acids and alkalis to form salts and water.