This set of Organic Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Cycloalkanes and Cycloalkenes”.
1. Cycloalkanes are associated with the general formula called __________
a) CnH2n+2
b) CnH2(n+2)
c) CnH2n+1-r
d) CnH2(n+1-r)
View Answer
Explanation: It is almost the same as that in the case of alkanes. Here the difference is that 2 is replaced by 1-r where r represents the number of rings in them.
2. Cycloalkanes have the same melting and boiling points as their corresponding alkanes.
a) True
b) False
View Answer
Explanation: The melting and boiling points of the cycloalkanes are much more than the corresponding alkanes.
3. Identify the incorrect statement regarding cycloalkanes.
a) These have sp3 hybridized carbons
b) These have tetrahedral bond angles
c) Stability of the cycloalkanes varies directly with their respective size
d) These undergo nucleophilic substitution reactions
View Answer
Explanation: Cycloalkane compounds do not have a perfect tetrahedral bond angle, instead they show a minor deviation from it which leads to destabilizing effect.
4. Identify the compound with the highest ring strain.
a) Cyclomethane
b) Cyclopropane
c) Cyclobutane
d) Cyclopentane
View Answer
Explanation: Cyclopropane is the compound with the highest ring strain. This is because the carbon atoms are arranged in the shape of a triangle thus forming C-C-C.
5. Which among the following compounds explodes on contact with oxygen?
a) Cyclopropane
b) Cyclobutane
c) Cyclopentane
d) Cyclohexane
View Answer
Explanation: Cyclopropane reacts very aggressively at ordinary temperatures and hence it explodes when comes in contact with oxygen.
6. Identify the incorrect statement regarding cyclobutane.
a) The carbon atoms in the cyclobutane are non-coplanar
b) These exist in nature as colourless gas
c) Cyclobutane is a commercially important compound
d) These compounds often show butterfly conformation
View Answer
Explanation: Cyclobutane is a compound which as no commercial and medicinal importance but the complex derivative forms of them are used for a variety of purposes.
7. Identify the alicyclic hydrocarbon which is highly flammable.
a) Cycloheptane
b) Cyclopentane
c) Cyclopropane
d) Cyclooctane
View Answer
Explanation: cyclopentane is a hydrocarbon with 5 carbon atoms and they are highly flammable.
8. Identify the incorrect statement regarding cyclohexane.
a) It is non-polar
b) It serves as an organic solvent
c) It a hydrophilic hydrocarbon
d) It is commercially used for variety of applications
View Answer
Explanation: This compound is a hydrophobic hydrocarbon as it is non- polar by nature.
9. Identify the incorrect statement regarding cycloalkenes.
a) The bonds in them are fewer compared to those in alkenes
b) They occur in gaseous form in nature
c) These undergo polymerization
d) The conjugated double bonds in them increase their stability
View Answer
Explanation: Cycloalkenes mostly appear in liquid state but sometimes they are even found in solid state.
10. Cycloalkene exhibits aromatic character.
a) True
b) False
View Answer
Explanation: Cycloalkene is a compound which has carbon atoms arranged in a closed ring but they do not exhibit aromatic character.
Sanfoundry Global Education & Learning Series – Organic Chemistry.
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