Question

Write the balanced equation of barium chloride + aluminium sulphate gives barium sulphate

Answer 1

The formula for barium chloride is BaCl2, aluminium sulphate is Al2(SO4)3, barium sulphate is BaSO4 and aluminium chloride is AlCl3, by the cross-valency rule. Hence, the skeletal equation is: 

BaCl2 + Al2(SO4)3 --> BaSO4 + AlCl3 

However, atoms of chlorine, aluminium and the polyatomic ion of sulphate are not balanced. The balanced equation would be: 

3BaCl2 + Al2(SO4)3 --> 3BaSO4 + 2AlCl3 

Note: The formulae can never be changed, i.e. the subscript must not change. Only the number of molecules can be changed, i.e. the change in number can be carried out only in front of the formula. 

A more informative way of expressing this reaction is by mentioning the physical states. 

3BaCl2(aq) + Al2(SO4)3(aq) --> 3BaSO4(ppt) + 2AlCl3(aq)

Answer 2

Answer:

3BaCl2(s) + Al2(SO4)3(s) ➝ 3BaSO4 + 2Al2Cl3(s)