Question

A compound contains atoms of three elements A,B And C. If the oxidation number of A is +2, B Is +5 and that Of C Is −2, the possible formula of the compound is

Answer 1

Step 1: Given

The oxidation numbers of the elements, A, B, C are $+2,+5\mathrm{and}-2$ respectively.

Step 2: Deriving possible formulae of compound

The formula of a compound with elements A, B, and C will be of the form

$A_x{B}_y{C}_z$

where x,y, and z are the atomicities of individual atoms respectively.

Step 3: Formula used

A compound is always neutral, so the oxidation number of the compound is zero.

Hence, the net oxidation number of the individual atoms is zero.

Hence calculating in a similar way,

$$\begin{gathered} =(+2)\left(\mathrm{x}\right)+(+5)\left(\mathrm{y}\right)+(-2)\left(\mathrm{z}\right)=0 \\ =2\mathrm{x}+5\mathrm{y}-2\mathrm{z}=0 \end{gathered}$$

Step 4: Applying the hit and trial method for the deriving formula for the compound

Restricting it to conditions that the maximum oxidation state could be $+8or-3$, by the Hit and Trial method, the possible solutions of (x,y,z) could be $(1,2,6)or(3,2,8).$

Both the sets are possible as the elements are unknown.

Hence the compounds are

$\mathrm{A}{\left({\mathrm{BC}}_3\right)}_2\mathrm{and}{\mathrm{A}}_3{\mathrm{B}}_2{\mathrm{C}}_8$