Practice question

Given: A first-order reaction has a rate constant of 0.01386 min^{-1 . What percentage of the reactant remains after 100 minutes? These values define the system as per NCERT data. Formula: ln frac[R]_0[R] = k t = 0.01386 × 100 = 1.386. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: frac[R][R]_0 = e^{-1.386 = 0.25, so 25% remains. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.