question_answer

The weight of iron which will be converted into its oxide \[(F{{e}_{3}}{{O}_{4}})\] by the action of 18 g of steam on it will be (At. wt. of Fe = 56)

A)  \[168\text{ }g\]           

B)         \[84\text{ }g\] 

C)  \[42\text{ }g\]            

D)         \[21\text{ }g\]

Correct Answer: C

Solution :

\[4\times 18g\,{{H}_{2}}O\equiv 3\times 56gFe\] \[\therefore \]   \[18g{{H}_{2}}O=\frac{3\times 56}{4}\] \[\equiv 42g\]