A,B and C are three elements which undergo chemical reactions according to the following equations. A 2 O 3 + 2B → B 2 O 3 + 2A 3CSO 4 + 2B → B 2 (SO 4 ) 3 + 3C 3CO + 2A → A 2 O 3 + 3C Answer the following questions with reasons. a. Which element is the most reactive? b. Which element is the least reactive? c. What is the type of reactions listed above?

Question

Philoid · Accepted Answer

(a) Element B is the most reactive element. Element B has replaced element A in the first reaction and also element B has replaced element C in the second reaction, so element B has to be the most reactive element.

(b) Element C is the least reactive element. Element C is replaced by both element A and B from its compound and hence it is the least reactive element.

(c) Reaction between oxide of A and element B is a reduction reaction as element A is reduced from its oxide state to its elemental state.

The reaction between sulphate of element C and B is displacement reaction in which a more reactive element [in this case B] replaces a less reactive element [in this case C] from its compound.

Reaction between oxide of C and element A is a reduction reaction as element C is reduced from its oxide state to its elemental state.