LOVE : Emotion or Chemical Reaction in Brain?

The topic which is in my mind,many people has already made many argument about this topic.But the common thing is that they did not find any conclusion.Yes,it is hard to make a conclusion about this whether love is emotion or some chemical reaction in brain.I am also very much sure that you also have your own opinion about this and have your own logic.I respect your thoughts and logic.
Now lets come to my thought.I believe that this is an undefined emotion.You cannot define it but this an emotional behavior.Now if you ask me how it becomes an emotion and there is nothing called emotion.All are the chemical reaction in brain then i will answer that if chemical reaction has its result.The result is always the same.You cannot change the result of a chemical reaction.For an example,2 oxygen and 1 hydrogen will also make water.They do not give you the result "Milk".Then if it is a chemical reaction and if it is happening every time then probably you will fall in love with every single man or woman that you see in your eyes.But the thing is not happening like this.You are falling in love with a particular person and not necessarily he is known to you previously.
I also believe another thing.I believe there must be some chemical reaction with the hormones that is why we feel physical attraction.But do not mix up physical reaction with love.These two thing are totally different.