Question

The formula of the sulphate of an element M is M2(SO4)3
.Write the formula of its
(a) Chloride (b) Oxide
(c) Phosphate (d) Acetate​

Answer 1

As the valency of the element M is = 3

a. M (Cl)3

b. M2(O)3

c. M (PO4)

d. M (CH3CO2)3

Answer 2

Answer: (a) Chloride: $MCl_3$

(b) Oxide:  $M_2O_3$

(c) Phosphate: $MPO_4$

(d) Acetate​: $(CH_3COO)_3M$

Explanation: For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

Here metal is having an oxidation state of +3 and sulfate is a polyatomic ion with oxidation state of -2. Thus they combine to form neutral $M_2(SO_4)_3$.

Thus the chloride will have a formula $MCl_3$ as chloride is having an oxidation state of -1, oxide will have a formula $M_2O_3$ as oxide is having an oxidation state of -2, phosphate will have a formula $MPO_4$ as phosphate is having an oxidation state of -3 and acetate will have a formula $(CH_3COO)_3M$ as acetate is having an oxidation state of -1.