Bases which dissolve in water

Notify me of follow-up comments by email. Notify me of new posts by email. Physics O Level Chemistry Contact. Aqueous Sodium Hydroxide is a strong alkali. Sodium hydroxide, Potassium hydroxide and Barium hydroxide are examples of strong alkalis.

Most of the alkali molecules remain unchanged in water as very few molecules are ionised to produce hydroxide ions. Ammonia and magnesium hydroxide are examples of weak alkalis. Basicity The basicity of an alkali refers to the number of moles of hydroxide ions that can be produced by one mole of alkali. Concentrated alkalis are just as dangerous as concentrated acids, sometimes more dangerous, but many people do not realise this. Bases react with oils and fats, so they are often used in household cleaners.

For example, drain cleaners and oven cleaners usually contain sodium hydroxide. Ammonia is also commonly used in cleaners, and it can be recognised by its choking smell.

It is wise to wear gloves when using these substances, otherwise they will react with your skin and burn it. Weak bases and alkalis are found in toothpaste, antacid tablets to help cure an upset stomach and baking powder. Bases and alkalis Bases v alkalis A base is a substance that can react with acids and neutralise them. Bases are usually: metal oxides, such as copper oxide metal hydroxides, such as sodium hydroxide, or metal carbonates, such as calcium carbonate Many bases are insoluble - they do not dissolve in water.

An acid is a substance that turns blue litmus red. Bases Bases are not common in the biological world as the chemistry of life has developed neutral or slightly acidic solutions to deal with most processes.

Sodium carbonate and washing soda are properly used household bases. Bases can be either water soluble or insoluble. Insoluble bases react with acids, directly dissolving in the acid as they react. Soluble bases form hydroxide ions in solution, that then react with the acid as described in the above section Acids, bases and water.

Caution: Base solutions are slippery or soapy to the touch. What is happening is the base is reacting with the oils in your skin to form soap, and it is your own oils that you are feeling as they turn into soap! Do not touch bases or get them near your eyes. Sodium hydroxide is particularly strong base and should not be handled at all. Neutralisation When an acid and a base are combined, water and a salt are formed. For example, when hydrochloric acid is mixed with sodium hydroxide, water and sodium chloride are formed.

Both hydrochloric acid and sodium hydroxide would dissolve you if you fell into them, but you can go swimming in the product of their reaction, salt water!