Question

What is the octane number of triptane?
(A)- 45
(B)- 25
(C)- 100
(D)- 125

Answer 1

Hint: Triptane whose IUPAC name is 2,2,3-trimethylbutane is an organic compound with molecular formula ${{C}_{7}}{{H}_{16}}$or ${{({{H}_{3}}C)}_{3}}-C-C-{{(C{{H}_{3}})}_{2}}H$ which is the most compact and heavily branched alkane compound of heptanes isomers and is the only with a butane backbone.

Complete answer:
-The standard measure of the performance of an engine or aviation gasoline is referred to as an octane rating or octane number.
-In simpler words, the ability of a fuel to resist knocking when ignited in a mixture with air in the cylinder of an internal combustion engine is referred to as Octane number or Antiknock rating.
-In an internal combustion engine, the sharp sound which is caused by the premature combustion of the part of the compressed air-fuel mixture in the cylinder is called knocking.
-The octane number is mathematically the percentage by volume of iso-octane in the iso-octane-heptane mixture that matches with the test fuel in a standard test engine.
-The higher the octane number, implies more are the compressions in the fuel which it can withstand before becoming detonating and hence higher the performance.
-A fuel with octane number as 0 is considered a poor fuel, while a fuel with octane number 100 is considered a good fuel. Iso-octane has the octane number of 100 and it shows minimal knock and heptanes have octane number as 0 and it shows bad knock.
-The octane number is calculated by comparing the knock intensity of the fuel at standard conditions with the blend of two reference fuels, iso-octane which resists knocking, and heptanes which knock readily.
The octane number of triptane is 125.

So, the correct answer is option D.

Note:
You should not get confused between triptane, triptan or tryptan. Triptane is an organic chemical compound, triptan is a type of anti-migraine drug while tryptan is the trade name of tryptophan of triplane. Octane number matters as in a spark-ignition engine, using fuel with too low octane rating can lead to pre-ignition and engine knock which can cause engine damage. Chemically, compressing the air-fuel mixture may cause fuel to detonate before the flame front from the spark plug reaches it.