Question

An organic compound having carbon, hydrogen and sulphur contains $4\%$ of sulphur. The minimum molecular weight of the compound is

• A. 200
• B. 400
• C. 600
• D. 800

Answer 1

Answer: (D)

The minimum molecular weight must contain at least one $S$ atom.
$\therefore \%S=\frac{\text{ weight of one }S\text{-atom }}{\text{ minimum molecular weight }}\times 100$
or, $4=\frac{32}{\text{ minimum molecular weight }}\times 100$
or, minimum molecular weight $=\frac{32}{1}\times 100=800$