A student addd few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, the added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate.
In which test tube or test tubes will she observe colour change? On the basis of this experiment, state which one is the most reactive metal and why ?

Explanation

`{:("Test tube A (Iron sulphate:)(aq)"),("Test tube B (Copper sulphate)(aq)"):}]Al`
`{:("Test tube C (Aluminium sulphate )"),("Test tube D (Copper sulphate)"):}]Fe`
In test tubes A , B and D the change in colour takes place.
It means Al displaces Fe from (aq) iron sulphate and Al also displaces copper from `CuSO_(4)` solution. This shows that Al is more reactive that Fe and Cu.
In this second experiment - Fe being less reactive than aluminium , does not displace Al from aluminium sulphate solution but displaces Cu from `CuSO_(4)` solution. thus 'Al' is the most reactive metal.