NEET2017ChemistryChemical KineticsActual
A first-order reaction has a specific reaction rate 10 - 2 sec - 1 ⁡ . How much time will it take for 20   g the reactant to reduce to 5   g ?
Options
- A238 . 6   second
- B138 . 6   second
- C346 . 5   second
- D693 . 0   second
Correct answer
B. 138 . 6   second
Step-by-step solution
t 1 2 = 0 .693 10 - 2   second For the reduction of 20   g   of reactant to 5   g , two t 1 2 is required. ∴       t = 2 × 0 .693 10 - 2   second = 138.6   s e c o n d