Ans.

Octane No.:- Octane number is defined as the percentage, by volume, of  iso-octane in the
mixture of iso-octane and h-heptane. It is the measure of rating of Spark Ignition engine.

Octane No. = (volume of Iso-Octane in unit quantity) / (volume of mixture of Iso-Octane + H-hapteane in unit quantity) * 100

Cetane No.:- Cetane number is defined as the percentage, by volume, of n-cetane in the mixture of
n-cetane and alpha methyl naphthalene. It is the measure of rating of Compression Ignition engine.

Cetane No. = (volume of n-cetane in unit quantity) / (volume of mixture of n-cetane + alpha methyl naphalene in unit quantity) * 100

Ans.

When material is compressed in one direction, it usually expands in either directions perpendicular to the direction of compression. This effect is called Poisson's effect
and  Poisson's ratio for:

Rubber = 0.5
Steel = 0.288
Wood < 0.2

Thus poisson's ratio is higher for Rubber.   

Ans.
dS =  dQ / T

Entropy is inversely proportional to the temperature. Thus on increasing temperature the entropy decreases.

One more thing to remember about entropy is for non reversible non cyclic processes entropy is always positive.   

Must Watch this video for complete understanding of Entropy. 
You will understand after watching this video; 
 - Entropy of substance at different states 
 - Entropy of surrounding or universe
 - " Tendency of nature is always to increase the entropy. " 

Ans:-
No, It will not work. It has high tendency to blast because petrol engine works on compression ratio of 6 to 10. And Diesel engine compression ratio lies between 15 to 22.

Thus on such high compression, gasoline (petrol) gets highly compressed beyond its flash point, which tend to cause a blast BhoOooooom !!!
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