Chemistry - Acids, Alkalis and salts

- Acids are substances which produce H+ ions when we add them to water.

- Bases are substances that will neutralise acids.

- An alkali is a soluble base. Alkalis produce OH- ions when we add them to water.

- We use the pH scale to show how acidic or alkaline a solution is.

- When we react an acid with a base a neutralisation reaction occurs.

- The reaction between an acid and a base produces salt and water.

- Salts can also be made by reacting a metal with an acid. This reaction also produces hydrogen gas as well as a salt.

- An indicator is needed when we produce a salt by reacting an alkali with an acid to make a soluble salt.

- Insoluble salts can be made by reacting two solutions to produce a precipitate.

- Precipitation is an important way of removing some substances from wastewater.