TestUstad

Which one of the following compounds shows intense knocking ?

Correct answer: D. n-heptane

  • A. n-pentane
  • B. iso-heptane
  • C. iso-octane
  • D. n-heptane

Explanation

Straight-chain hydrocarbons knock more readily because their combustion is less smooth and they have lower octane numbers than highly branched hydrocarbons. n-Heptane is assigned an octane number of 0 and is therefore the best choice; iso-octane is the likely distractor because its name is associated with the high-octane reference fuel.

Written and checked by , M.Phil ChemistryLast updated
Report an error

The more specific you are, the faster it gets fixed. A source beats an opinion.

Prefer email? [email protected]

About Alkanes

Alkanes are saturated hydrocarbons containing only carbon-carbon and carbon-hydrogen single bonds, with the general formula CnH2n+2 for open chains. Their structure, isomerism, IUPAC nomenclature, physical properties, combustion, free-radical halogenation and conformations are covered, including the difference between substitution in alkanes and addition in unsaturated hydrocarbons.

Practise Chemistry of Hydrocarbons

1,091 free Chemistry of Hydrocarbons MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

Start a free Chemistry of Hydrocarbons testAll Chemistry of Hydrocarbons MCQs

Discussion

Stuck on an option, or know a faster way to get there? Ask or explain it here.

No comments yet. Be the first to explain this one.

Exams that ask Chemistry questions like this

Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.

Lecturer Chemistry Test Chemistry80 MCQsSubject Specialist Chemistry Test Chemistry80 MCQsDUHS Chemistry45 MCQsETEA MDCAT Chemistry45 MCQsKMU Chemistry45 MCQsMDCAT Chemistry45 MCQsNUMS Chemistry40 MCQsECAT Chemistry30 MCQsETEA Engineering Admission Test Chemistry30 MCQsGIKI Chemistry30 MCQsNED Chemistry30 MCQsNET Chemistry30 MCQsPIEAS Chemistry30 MCQsBSN Entry Test Chemistry25 MCQs

More Alkanes questions

the fractional distillation of petroleum produces gasoline up to ________________?

Alkanes containing a methyl group on main chain at 2nd carbon are called________________?

Hydrogenolysis results in the formation of________________?

At low temperature and pressure cracking can be done in presence of catalyst________________?

Crude oil is blackish coloured liquid produced after the decay of organic matter present between_________________?

Coal is produced after a long time decay of_________________?