A--> 3.2 R The second order gas phase reaction is carried out in a batch vessel at a total pressure of 5 atm and a temperature of 350 K. It is known that the reaction system initially consists of 70% A gas, 20% inert gas and 10% R. 60% volume 7 minutes after reaction start According to the change; a) Calculate the k-velocity constant of the reaction. b) Calculate the time taken for 80% conversion.