The weight of iron which will be converted into its oxide(Fe₃O₄) by the action of 18 g of steam on it will be (at. wt. of Fe=56)

Options

(a) 168 g
(b) 84 g
(c) 42 g
(d) 21 g

Correct Answer:

42 g

Explanation:

3Fe + 4H₂O → Fe₃O₄ + 4H₂
3x 56 g 4x 18 g
= 168 g = 72 g
72 g steam requries Fe= 168 g
18 g steam requires Fe= 168x 18/72
= 42 g