A base is defined as a substance that contains hydroxide ions (OHˉ) when dissolved in water.
A base can also be defined as a substance which accepts oxide or hydroxide ions.
Bases have different solubility
Most are insoluble in water, Copper (II) Oxide, Lead (II) oxide
Bases which are soluble are called alkalis., Sodium hydroxide, Calcium hydroxide
Alkalis have a bitter taste and soapy feel
Alkalis turn red litmus blue.
Alkalis only show their alkaline properties when dissolved in water, This is because it is the hydroxide ions that give alkalis its properties
Alkalis, like acids, are also good electrical conductors
Neutralisation, Acid + Alkali => Salt + Water, E.g. Sodium Hydroxide + Sulfuric Acid =>Sodium Sulfate + Water
Alkali + Ammonium salt => Ammonia + Water + Salt
Example: Sodium hydroxide + Ammonium Chloride=> Sodium Chloride + water + Ammonia, Test for Ammonia gas: If a colourless, pungent gas that turns damp red litmus paper blue is produced, the gas is ammonia.
Alkali(of metal A) + salt(of metal B) => Metal B hydroxide + salt(of metal A), Sodium hydroxide + Copper(II) sulfate=> sodium sulfate + Copper(II) hydroxide, If metal B hydroxide is soluble, reaction will not take place
Ammonia Solution, Window cleaning solutions, Fertilisers
Sodium Hydroxide, Soaps and Detergents, Industrial-cleaning detergents
Magnesium hydroxide, Toothpaste, Antacids
Calcium oxide, Neutralizing acidic soil, To make iron, concrete and cement
An acid is a substance that dissociates to form hydrogen ions when dissolved in water.
Organic acids contain carbon and are found in living things., Lacitc Acid, Citric Acid, Ethanoic Acid
Inorganic acids do not contain carbon and are commonly found in science laborities., Hydrochloric Acid, Sulfuric Acid
Acids reacts with certain metals to form a salt and hydrogen gas, When a reactive metal, e.g. magnesium, is added to an inorganic acid like hydrochloric acid or sulfuric acid, effervescense will be observed., The reactive metal will dissolve and the reaction will give out heat., The bubbles of gas produced contain hydrogen gas., Hydrogen gas can be tested by inserting a lighted splint into a test tube. If the gas is hydrogen, the splint will extinguish with a 'pop' sound., Unreactive metals like copper and silver will not react with acids
Acids react with all carbonates to produce a salt, water and carbon dioxide gas., When a carbonate compound, e.g. calcium carbonate, is added to an inorganic acid like hydrochloric acid or sulfuric acid, effervescence will be observed., The bubbles of gas produced contain carbon dioxide gas., Carbon dioxide can be tested for by bubbling the gas into calcium hydroxide solution, also known as limewater. If the gas is carbon dioxide, a white precipitate will be observed in the calcium hydroxide solution.
Acids react with metal oxides/hydroxides to give a salt and water, Types of oxides, Acidic Oxides, Are oxides of non-metals, Most acidic oxides are soluble in water and will give an acid(e.g. carbon dioxide dissolves in water to give carbonic acid), Basic Oxides, Are oxides of metals, Most basic oxides are insoluble in water except for a few(e.g. sodium oxide, potassium oxide), Amphoteric Oxides, Are metallic oxides that react with both acids and bases to form a salt and water, Examples:Aluminium oxide, Lead(II) oxide, Zinc oxide, Neutral Oxides, Shows neither basic or acidic properties, Examples: Water, Carbon monoxide and nitric oxide
Acids taste sour.
Acids turn blue litmus red.
Acids are good electrolytes i.e. they are good conductors of electricity., This is because the hydrogen ions are able to move about freely in the acid and thus can carry the electric charge
Hydrochloric Acid, Removes Rust
Sulfuric Acid, Used in car batteries
Nitric Acid, Making explosives, Fertilizers