Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NTA Abhyas JEE Main2020ChemistryChemical KineticsPractice

The rate constant for the first order decomposition of a certain reaction is described by the equation: log k s -1 = 14.34 - 1.25 × 10 4 K T At what temperature will its half-life period be 256 min ?

Options

  1. A239.33 kJ ; 669 K
  2. B259.33 kJ
  3. C329.33 kJ
  4. D539.33 kJ

Correct answer

A. 239.33 kJ ; 669 K

Step-by-step solution

When half-life = 256 min, k = ln 2 t 1 / 2 = 0.693 256 × 6 0 s -1 = 4.5 × 1 0 - 5 s -1 ⇒         1.25 × 10 4 T   =   14.34 −   [ l o g   4.5 × 10 − 5 ] ⇒    14 .34 - [ -5+0 .65 ] ⇒ 1 9 · 3 4 - 0 · 6 5 = 1 8 · 6 9 T = 12500 18.69 = 669K

Practice Chemical Kinetics on Quantrex Academy →

More from Chemical Kinetics

For a reversible reaction R P , at constant temperature, both the forward and the backward reactions are first order elementary reactions with rate constants k_f and k_b , respecti 2026For a first-order reaction R P at a given temperature, k is the rate constant. For this reaction, at the given temperature, the concentrations of R and P at a time t are [ R ] and 2026Given below are two statements: R=8.314 J K ⁻¹ mol ⁻¹ and 1 cal =4.2 J Statement I: When E_a=12.6 kcal/mol, the room temperature rate constant is doubled by a 10 ,^ C increase in t 2026Decomposition of a hydrocarbon follows the equation k = (5.5 10¹¹ , s ⁻¹) ,e^ -28000 , K T . The activation energy of reaction is __________ kJ mol ⁻¹ . (Nearest Integer) Given : R 2026For a reaction A P at T K , the half life (t_ 1/2 ) is plotted as a function of initial concentration [A]₀ of A as given below. The value of x in the given figure is _______ s (Nea 2026First order gas phase reaction A B + C p_i = initial pressure of gas A, p_t = total pressure of the reaction mixture at time t Expression of rate constant ( k ) is 2026If the half life of a first order reaction is 6.93 minutes then the time required for completion of 99 % of the reaction will be _____ minutes. (Given : 2 = 0.3010 ) 2026Consider the given graph showing variation of reactant concentration with time. Three different reactions were started with identical initial concentration of reactants. Which of t 2026 Full Chemical Kinetics list All NTA Abhyas JEE Main PYQs