Four students P, Q, R and S noted the initial colour of the solutions kept in beakers I, II, III and IV. After inserting zinc rods in each solution and leaving them undisturbed for two hours, the colour of each solution was again noted in the form of table given below :
Which student noted the colour change in all the four beakers correctly?
the correct answer is not given because acc. to reactivity series only beaker 1 will have some change