Potassium metal reacts with water to give potassium hydroxide and hydrogen gas. Write a ba lanced chemical equation for this reaction.

21 What is a balanced chemical equation? Why should chemical equations be balanced? 21 Aluminium burns in chlorine to form aluminium chloride (AlCl₃). Write a balanced chemical equation for this reaction. 22 Explain, with example, how the physical states of the reactants and products can be shown in a chemical equation. 22 Balance the following equation and add state symbols:

Zn + HCl ZnCl₂ + H₂