Some Basic Concepts Of Chemistry Question 10
Question: A gaseous hydrocarbon gives upon combustion, 0.72 g of water and 3.08 g of $ CO _2 $ The empirical formula of the hydrocarbon is
Options:
A) $ C _2H _4 $
B) $ C _3H _4 $
C) $ C _6H _5 $
D) $ C _7H _8 $
Show Answer
Answer:
Correct Answer: D
Solution:
18 g $ H _2O $ contains 2 g H.
$ \therefore $ 0.72 g $ H _2O $ contains 0.08 g H 44 g $ CO _2 $ contains 12 g C.
$ \therefore $ 3.08 g $ CO _2 $ contains 0.84 g C.
Elements Wt. Wt./at. mass Simple Ratio Simple Whole ratio
C 0.84 0.84/12 0.07 7
H 0.08 0.08/1 0.08 8
$ \therefore $ Empirical formula = $ C _7H _8 $
