Question

Compound A and B are two oxides of sulfur. Compound A is $50$% sulfur by mass, while Compound B is $40$% sulfur by mass.
Given the atomic masses of sulfur and oxygen are $32amu$ and $16amu$, respectively, which of the following statements is NOT a valid interpretation of these data?

• A. Compound A could have the formula, $S{O}_2$
• B. Compound B could have the formula, $S{O}_2$
• C. Compound A and B illustrate Dalton's law of multiple proportions.
• D. Compound A could have the formula, $SO$.

Answer 1

Answer: (B), (D)

Compound B could have the formula, $S{O}_2$
Compound A could have the formula, $SO$.

Let, oxide A contain $50$% sulphur.

Atomic weight of sulphur=$32g$ and constitutes $50$% molecular weight of the oxide.

Thus, the molecular mass=$32\times 2=64g$

Atomic mass of $O=16g$

Thus, $32g$ will contain $2$ atoms of $O$.

$\therefore$ formula of oxide=$S{O}_2$

Similarly,

% of $S=40$% for oxide B

So, total mass of oxide=$\frac{32}{40}\times 100=80g$

Mass of oxygen=$80-32=48g$

No. of $O$ atoms=$\frac{48}{16}=3$

So, formula of oxide=$S{O}_3$

So, the answer is B and D.