Question

A compound contains three elements $X,Y$ and $Z$. The oxidation number of $X,Y$ and $Z$ are $+3,+5$ and $-2$ respectively. The possible formula of the compound is:

• A. $X_{2}YZ$
• B. $XY{Z}_3$
• C. $X_3(Y{Z}_4{)}_3$
• D. $X_2{Y}_{2}Z$

Answer 1

The correct option is C $X_3(Y{Z}_4{)}_3$

The sum of all oxidation values must be equal to zero. Let, number of atoms of $X,Y$ and $Z$ are respectively $a,b$ and $c$.

Then, $(+3)a+(+5)b+(-2)c=0$
or $3a+5b-2c=0$

Now, putting values of a, b and c for all the given options, which wil give sum equal to zero, will be our formula.

(a) For, $X_{2}YZ$
$a=2$
$b=1$
$c=1$
Thus, $3a+5b-2c=0$
$3\times 2+5-1\ne 0$

(b) For, $XY{Z}_3$
$a=1,b=1,c=3$
$3a+5b-2c=0$
$3+5-6\ne 0$

(c) $X_3(Y{Z}_4{)}_3$
$a=3,b=3,c=12$
$3a+5b-2c=0$
$(3\times 3+5\times 3)-(2\times 12)=0$
$9+15-24$
$24-24=0$

(d) $X_2{Y}_{2}Z$
$a=2,b=2,c=1$
$3a+5b-2c=0$
$(3\times 2)+(5\times 2)-(2\times 1)=0$
$6+10-2\ne 0$.

Hence, option (C) is the correct answer.