Metals Reacting with Water & Acids (Edexcel IGCSE Chemistry)

• 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

Reactions of metal with cold water summary table

Metal	Reaction with water
Most reactive
Potassium	Reacts violently
Sodium	Reacts quickly
Lithium	Reacts less strongly
Calcium	Reacts less strongly
Magnesium
Zinc
Iron	Slow rusting
Copper
Least reactive

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:

Table of acid-metal reactions

Metal	Sulfuric acid	Hydrochloric acid
Magnesium	Mg (s) + H2SO4 (aq) → MgSO4 (aq) + H2 (g)	Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
Zinc	Zn (s) + H2SO4 (aq) → ZnSO4 (aq) + H2 (g)	Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
Iron	Fe (s) + H2SO4 (aq) → FeSO4 (aq) + H2 (g)	Fe (s) + 2HCl (aq) → FeCl2 (aq) + H2 (g)