Acids Bases & Salts (Salts)

an e-learning series by ycs

Learning Objectives

• By the end of the lesson, pupils would be able to– explain how salts are formed from acids– name common soluble and insoluble salts– describe the preparation of soluble and

insoluble salts

Salts from Acids

• When the hydrogen atom(s) of the acids is/are replaced by a metal or ammonium ion, a salt is formed.

• HNO3, if replaced by Na+, NaNO3 is formed

• HCl, if replaced by NH4+, NH4Cl is

formed

Solubility of Salts

• All nitrates are soluble in water.• All potassium, sodium salts are soluble in

water.– Al(NO3)3, Pb(NO3)2

– KCl, Na2SO4

• Common insoluble salts are– PbSO4

– AgCl– BaSO4

Preparing Soluble Salts

• Potassium nitrate– Reactants : KOH, HNO3

– Method : using titration with a suitable indicator, salt produced would not be contaminated with excess acid/alkali

Preparing Soluble Salts

• Copper(II) sulphate– Reactants : CuO, H2SO4

– Method : add excess CuO to H2SO4, filter away the excess CuO and crystallise the salt out from the solution.

Preparing Insoluble Salts

• Begin with two soluble salts containing the ions of the salt that you wish to prepare.

• Lead sulphate– Reactants : Pb(NO3)2, Na2SO4

– Method : mix both solutions together, the insoluble salt will be formed as precipitate, filter away the mixture to obtain the ppt, wash and dry

– Ionic equation : Pb2+ (aq) + SO42- (aq) PbSO4(s)

• Name the reactants needed to produce,– calcium chloride– Iron(II) sulphate– copper(II) nitrate

Nutshell Activity

• Describe a method to prepare– sodium nitrate– silver chloride– Iron(II) sulphate

Nutshell Activity