Question

Choosing only substances from the list given in the box below , write equations for the reactions which you would use in the laboratory to obtain :

Dilute sulphuric acid. Copper Copper carbonate
Iron Sodium carbonate
Sodium
Zinc

(a) Sodium sulphate
(b) Copper sulphate
(c) Iron (II) sulphate
(d) Zinc carbonate

Answer 1

(b) copper sulphate

Copper does not react with dilute sulphuric acid as its reduction potential is higher than that of hydrogen. Copper does not displace hydrogen from non-oxidising acids like HCl or dilute H2SO4.

But, concentrated sulphuric acid is an oxidising agent. So, when copper is heated with conc.H2SO4, a redox reaction occurs and the acid gets reduced to sulphur dioxide.

Cu + 2H2SO4 = CuSO4 + SO2 + 2H2O

CuC03 + H2SO4 -> CuSO4 + H20 + CO2

(a) Sodium Sulphate

You don't want to be there when that reaction starts, it's extremely violent.
2 Na + H2SO4 = Na2SO4 + H2
Sodium sulphate and hydrogen gas are the reaction products.

Na2CO3 + H2SO4 -> Na2SO4 + H2O + CO2

(c) Iron(II) Sulphate

There are two potential reactions that can take place - with dilute H2SO4, you get a standard metal-acid redox reaction - Iron (II) Sulphate & hydrogen gas are the products:

Fe (s) + H2SO4 (aq) → FeSO4 (aq) + H2 (g)

In hot concentrated solutions, the acid acts as an oxidising agent, the redox reaction producing iron (III) sulphate, water and sulphur dioxide gas

2Fe (s) + 6H2SO4 (l) → Fe2(SO4)3 (aq) + 3SO2 (g) + 6H2O (l)

(d) Zinc Carbonate

Zinc carbonate is not formed from the above given compounds
it is formed by this reaction

ZnSO4(aq) + Na2CO3(aq) → Na2SO4(aq) + ZnCO3(s)