question_answer

n-hexadecane (cetane) has cetane number

A)  110                                       

B)  90

C)  100                                       

D)  zero

Correct Answer: C

Solution :

                 The quality of diesel fuel is expressed in terms of cetane number. Cetane number of a sample of diesel is the percentage of cetane by volume in a mixture of cetane and \[\alpha \]-methylnaphthalene which has the same ignition properties as the diesel under examination in a test engine. Cetane (n-hexadecane) ignites rapidly and is given a cetane number of 100, whereas \[\alpha \]-methyl-naphthalene ignites slowly and is given a cetane number of zero.                 \[\underset{\begin{smallmatrix}  cetane\text{ }\left( n-hexadecane \right) \\  cetane\text{ }no.\text{ }=\,\,100 \end{smallmatrix}}{\mathop{C{{H}_{3}}-{{(C{{H}_{2}})}_{14}}-C{{H}_{3}}}}\,\]                 \[\alpha \]-methyl naphthalene cetane no. = 0