A student took four test-tubes I, II, III and IV containing aluminium sulphate, copper sulphate, ferrous sulphate and zinc sulphate solutions respectively. He placed iron strips in each one of them. After some time, he found a brown deposit formed in test-tube marked :

(1) I
(2) II
(3) III
(4) IV

Q. A student took four test-tubes containing solutions of different colours marked I, II, III and IV as shown here. The test-tubes containing copper sulphate solution and ferrous sulphate solution could be the tubes :

(1) I and III
(2) II and III
(3) III and IV
(4) II and IV

Q.

A student took four test tubes containing solutions of different colours marked I (colourless) II(Blue), III (Orange) and IV (Pale green) .
Which of the tubes contain copper sulphate solution and ferrous
sulphate solution?

Q. A student takes Cu, Al, Fe and Zn pieces separately in four test tubes labelled as I, II, III, and IV respectively. He adds 10 mL of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case.

He would observe a black residue in the test tubes :
(1) (I) and (II)
(2) (I) and (III)
(3) (II) and (III)
(4) (II) and (IV)

Q. Solutions of copper sulphate, iron sulphate and zinc sulphate are prepared and marked I, II and III respectively. Few pieces of aluminium are added to each solution. After some time a change will be observed in:

Q. A student added 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, she 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.