NTA Abhyas JEE Main2020ChemistryChemical KineticsPractice
The gas phase decomposition of dimethylether follows first order kinetics C H 3 - O - C H 3 g → C H 4 g + H 2 g + C O g The reaction is carried out in constant volume container at 500 o C and has a half-life of 14 .5 min . Initially only dimethylether is present at a pressure of 0 .40 atm . The total pressure of the system after 12 min is x 100 atm . The value of x is [Given 10 0 .25 = 1 .778 ]
Correct answer
75
Step-by-step solution
Now: 12 = 2.303 0.693 × 14.5 log 0.4 0.4 - x 0.25 = log 0.4 0.4 - x 1 0 0.25 = 0.4 0.4 - x 0.4 0.4 - x = 1.778 ⇒ x = 0.175 Total pressure = 0.4 - 0.75 + 0.175 + 0.175 + 0.175 = 0.75 a t m now: x 100 = 0.75 x = 75