Q:

Is it possible to take a liquid/gas inside aircraft cabin to contaminate the air?

As per the security rules, i think upto 100ml of liquid ( medicines, perfumes etc) can be taken on-board by a passenger but is it possible that, that 100ml can be converted to fumes/gas and contaminate the air inside the aircraft?
Any such incident has ever been reported?

A:

To answer your first question: it depends what you mean by "contaminate". The air in an aircraft cabin is constantly being renewed every two or three minutes (source (Airbus) - Boeing aircraft are similar), and the airflow pattern is such that the air only flows "across" the cabin, not along it. In other words, any contaminant you introduce will only reach the passengers seated in the same row as you (and perhaps the rows directly behind and in front of you), and will only stay there for a few minutes before the air exchange carries it overboard. 
About 50% of the air which leaves the cabin is recycled back into the cabin, but it passes through filters first, which will stop any particles but will let gases through. Statistically, the concentration of whatever was introduced will drop to nearly zero after two passes through the ventilation system (due to dilution with fresh outside air). 
My understanding is that the "100ml" rule is more designed to stop passengers from building liquid explosives aboard an aircraft (source (TSA)) than to stop them introducing harmful contaminants into the air. 
I don't know of any incidents where an airborne substance was used maliciously in an airplane cabin, but you would get a similar effect through an on-board fire. The aircraft's ventilation system is designed to clear the cabin and flight deck of smoke within a short period of time (often by disabling the air recirculation system and increasing the fresh air flow into the aircraft). 

A:

Gases
For it to be converted to a gas, it would have to either be stored in a pressurized container or be a liquid that happens to vaporize at room temperature in the relatively small pressure difference between the surface and the cabin pressure altitude. Pressurized gas containers are not allowed on board U.S. airline flights unless they are:

Medical oxygen cylinders with in-tact and unmodified regulator valves,
Part of a life vest, or
Verifiably empty.

From the TSA Prohibited Items List:
Allowed in checked or carry-on luggage:

Small compressed gas cartridges
  (Up to 2 in life vests and 2 spares. The spares must accompany the life vests and presented as one unit)

Not allowed in any luggage:

Fire extinguishers and other compressed gas cylinders

From the "Can I bring my...?" search blank on the same page with the search term "compressed gas cylinder":

Except for personal medical oxygen cylinders, you can only carry an EMPTY compressed gas cylinder on board a plane. To be permitted (in either carry-on or checked baggage), it must be clearly visible to the Transportation Security Officer (TSO) that the cylinder is empty. Personal oxygen is permitted if the regulatory valve has not been tampered with or removed.  

Aerosols
Aerosols are allowed, but are subject to the same 3-1-1 rule as other liquids, that is, they must be in a 100 mL or less container which is then stored inside a 1 L / 1 qt. zip-top bag. As Lightsider mentioned, these will almost certainly be filtered out of the air by the air filters in the ventilation system, as they are not in gaseous form (and likely are relatively large particles and/or molecules.)
From the same TSA page using the search term "aerosols," you get the following:

You may carry liquids, gels and aerosols in your carry-on bags only if they adhere to the 3-1-1 rule: containers must be 3.4 ounces or less; stored in a 1 quart/liter zip-top bag; 1 zip-top bag per person, placed in the screening bin. Larger amounts of non-medicinal liquids, gels, and aerosols must be placed in checked baggage.

