Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2009ChemistryChemical KineticsActual

If 50 % of a radioactive substance dissociates in 15 min , then the time taken by substance to dissociate 99 % will be

Options

  1. A50 min
  2. B100 min
  3. C99 min
  4. D150 min

Correct answer

C. 99 min

Step-by-step solution

Radioactive disintegration is a Ist order reaction, hence aligned k & = 2.303 t a a-x k & = 2.303 15 100 100-50 also k & = 2.303 t 100 100-99 2.303 15 100 50 & = 2.303 t 100 1 1 15 2 & = 1 t 100 0.3010 15 & = 2 t t & = 2 15 0.3010 =99 ~min aligned

Practice Chemical Kinetics on Quantrex Academy →

More from Chemical Kinetics

The combination of NO ₂(g) and CO (g) occurs in two steps as follows: What is the rate law for the reaction? 2 NO ₂ NO + NO ₃(k₁) - slow NO ₃ + CO CO ₂ + NO ₂(k₂) - fast 2026The slope of the graph [ A ]_t against time for zero order reaction is 2026For the reaction C ₂ H ₅ Br _ (l) C ₂ H _ 4(g) + HBr , r = K( C ₂ H ₅ Br ) What is order and molecularity of the reaction respectively ? 2026The decomposition of N ₂ O _ 5(g) occurs as: 2 N ₂ O _ 5(g) 4 NO _ 2(g) + O _ 2(g) . If initial concentration of N ₂ O _ 5(g) is 1.63 10⁻² mol L ⁻¹ and after 400 seconds it is 1.36 2026Which of the following statements represents rate of reaction? 2026What is the order of reaction for the following? 2 H ₂ O ₂(l) 2 H ₂ O (l) + O ₂(g) 20262 A k B is a zero-order reaction, where k=1.0 mol L ⁻¹ min ⁻¹ . If the initial concentration of A is 2 M, then the time taken to complete 75 % of the reaction will be 2026Match List I with List II : List I (Order of reaction) List II (Unit of rate constant) A. Zero order I. mol ⁻¹ L s ⁻¹ B. First order II. mol ⁻² L ² s ⁻¹ C. Second order III. s ⁻¹ D 2026 Full Chemical Kinetics list All NEET PYQs