Molecularity of Reaction

Q. Which of the following are the acceptable values for molecularity of a reaction?

1. 2
2. 0
3. 0.5
4. -1

Q. Who has made formulae in Science and why?

Q. Who has made the formulae in science and why?

Q. Which of the following statements about molecularity of any reaction are incorrect?

1. It is experimentally determined
2. It is meant for the reaction and not for its individual steps
3. It may or may not be whole number.
4. It can never be zero

Q. Now, two reactions are given to Karthik and Arun one each, to find the molecularity of the reaction. Considering that both reactions are elementary.
Reaction (A) is $N{H}_{4}N{O}_2\to N_2+2H_{2}O$
Reaction (B) is $2HI\to H_2+I_2$
Karthik got the answer as 2 and Arun got answer as 1, which are correct by the way. Can you tell which reactions are given to Karthik and Arun?

1. Karthik – Reaction A, Arun reaction B
2. Arun – Reaction A, Karthik Reaction B