What is observed when hot concentrated caustic soda solution is added to

(a) Zinc and

(b) Aluminium?

Write balanced equations.

A student was asked to perform two experiments in the laboratory based on the instructions given:
Observe the picture given below and state one observation for each of the Experiments 1 and 2 that you would notice on mixing the given solutions.

(a) Experiment 1

(b) Experiment 2

(a) What do you understand by amphoteric oxide?

(b) Give the balanced equations for the reaction with two different amphoteric oxides with a caustic alkali.

(c) Name the products formed.