Some Basic Concepts Of Chemistry Question 123
Question: When $ FeS _2 $ is burnt in air, it converts into $ Fe _2O _3. $ The change in percentage by weight of iron in the process is (Fe = 56)
Options:
A) 23% increase
B) 12% decrease
C) 12% increase
D) no change
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ \underset{Fe\frac{56}{120}\times 100=46.67}{\mathop{\underset{56+32\times 2=120}{\mathop{FeS _2}},}},\xrightarrow[{}]{{}}\underset{\frac{112}{160}\times 100,=,70}{\mathop{\underset{56\times 2+3\times 16,=160}{\mathop{Fe _2O _3}},}}, $ Percent increase = 70 46.67 = 23% (approx.)
