Question

As per the Euro $\;III$ norms for gasoline, the benzene content should be:
A.$1\% $
B.$2\% $
C.$3\% $
D.$4\% $

Answer 1

Hint:The Euro norms are the set of regulations which help to curb the release of harmful gases and benzene. The addition of benzene to fuels increases the efficiency of the fuel but at the same time poses a great risk to the health of humans as it can be a carcinogen.

Complete step by step solution:
The Euro Norms $\;III$ or Bharat stage $\;III$ was enacted in the year $2010$ in an effort to decrease the emission of different harmful gases like carbon monoxide, nitric oxide and gases belonging to the photochemical smog like PAN that is, poly acrylonitrile.
In addition to these gases we also have carcinogens like benzene present in the exhaust fumes that is emitted from vehicles. This has to be regulated as it has a tendency of causing cancer. The maximum amount of benzene concentration that is permitted in the exhaust fumes is $1\% $ . in addition to this there are two differences that are seen between the Euro Norms $$\;III$$ and Euro four norms. One is that all bikes or two wheelers were said to contain combined or automatic braking and the other difference was that the Euro four norms had considered many more gases as harmful gases.
Benzene is added to motor fuels or gasoline in order to increase the octane number and reduce knocking. Octane number refers to the anti-knocking ability of a fuel using isooctane and heptane mixture as a standard of measurement. The word knocking on the other hand refers to the phenomenon where the engine of a vehicle undergoes damage due to the premature combustion of fuels. This can increase the wear and tear of the vehicle.
Therefore, the answer to the question will be option A that is $1\% $ .

Note:
Benzene is used as an anti knocking agent in fuels.
It is an aromatic hydrocarbon and can also cause cancer.
According to the Euro $\;III$ norms for gasoline, the benzene content should be only $1\% $ of the total volume of fuels.