a) A, B and C are 3 elements which undergo chemical reaction according to following equations
a) ` A_2O_3 +2B to B_2O_3 + 2A`
b) ` 3CSO_4 + 2B to B_2(SO_4)_3 + 3C`
c) ` 3CO + 2A to A_2 SO_3 + 3C`
Answer the following:
i) Which element is most reactive? ii) Which element is least reactive? b) Why is ZnO called amphoteric oxide? Name another amphoteric oxide.

Explanation

a) i) Most reactive element is B as it has replaced both A and C from their compounds.
ii) Element C is least reactive as it has been replaced both by A and B
b) Zinc oxide (ZnO) is called amphoteric oxide as it behaves both as acidic oxide and basic oxide.
`underest("basic oxide")(ZnO) + underset("acid")(2HCl) to underset("zinc chloride")(ZnCl_2) + H_2O`
`underset("acidic oxide")(ZnO) + underset("base")(2NaOH) to underset("sodium zincate")(Na_2ZnO_2) + H_2O`
Alluminium oxide `(Al_2O_3)` is another amphoteric oxide.