Metals Reacting with Water & Acids (Edexcel IGCSE Chemistry: Double Science)

• The chemistry of the metals is studied by analysing their reactions with water and acids
• Based on these reactions a reactivity series of metals can be produced
• The series can be used to place a group of metals in order of reactivity based on the observations of their reactions with water and acids

Reaction with water

• The reactions of potassium and sodium have already been seen previously in the alkali metals, but the reaction with calcium and water is given here for reference:

Ca (s) + 2H₂O (l) ⟶ Ca(OH)₂ (aq)  + H₂(g)

calcium + water ⟶ calcium hydroxide + hydrogen

• The reactions with magnesium, iron and zinc and cold water are very slow

Reaction with dilute sulfuric or hydrochloric acids

• Only metals above hydrogen in the reactivity series will react with dilute acids
• The more reactive the metal then the more vigorous the reaction will be
• Metals that are placed high on the reactivity series such as potassium and sodium are very dangerous and react explosively with acids
• When acids react with metals they form a salt and hydrogen gas:
• The general equation is:

metal + acid ⟶ salt + hydrogen

• Some examples of metal-acid reactions and their equations are given below:

Acid-Metal Reactions Table