Organic Chemistry Multiple Choice Questions on “Polyhalogen Derivatives”.
1. What will be the product for the given reaction?
a) CCl3CHO
b) C6H6Cl6
c) C6H12Cl6
d) C6H9Cl2
Answer: b
Clarification: Benzyl hexachloride will be formed when Benzene reacts with chlorine in presence of U.V light.
C6H6 + 3Cl2 + U.V light → C6H6Cl6
Benzene BHC
2. The molecular formula of DDT has how many chlorine atoms?
a) 5 chlorine atoms
b) 2 chlorine atoms
c) 3 chlorine atoms
d) 4 chlorine atoms
Answer: a
Clarification: As we can in below molecular structure of DDT has 5 chlorine atoms.
3. What is the IUPAC name of chloroform?
a) Dichloromethane
b) Trichloromethane
c) Chloromethane
d) Carbon tetrachloride
Answer: b
Clarification: Chloroform, or trichloromethane, is an organic compound with formula CHCl3. It is a colorless, sweet-smelling, dense liquid that is produced on a large scale as a precursor to PTFE.
4. Which among the following is true?
a) Freon does not initiate radical chain reactions in stratosphere
b) Iodoform initiates radical chain reactions in stratosphere
c) Freon initiates radical chain reactions in stratosphere
d) Chloroform initiates radical chain reactions in stratosphere
Answer: c
Clarification: Freon (Eg: CFCl3– Freon11) does initiate radical chain reactions in stratosphere, which can upset the ozone layer.
5. CFxCly [where x + y = 4], why these compounds are not used?
a) These are fluoro carbons
b) These are difficult to synthesise
c) They deplete ozone layer
d) These are very expensive
Answer: c
Clarification: CFC molecules are made up of chlorine, fluorine and carbon atoms and are extremely stable. This extreme stability allows CFC’s to slowly make their way into the stratosphere (most molecules decompose before they can cross into the stratosphere from the troposphere).
6. Which one of the following is the correct formula of methylene dichloride?
a) ClCH = CHCl
b) ClC ≡ CCl
c) CH2Cl2
d) CH2(Cl) CH2Cl
Answer: c
Clarification: As we can see below molecular diagram of methylene dichloride the correct molecular formula is CH2Cl2.