A first order reaction has rate constant 1 × 1 0 − 2 s − 1 . What time will it take for 20 g of reactant to reduce to 5 g ?

(A) k = 1 × 1 0 − 2 s − 1 , [ A ] 0 = 20 g , [ A ] t = 5 g For first order reaction, t = k 2.303 lo g 10 [ A ] t [ A ] 0 ∴ t = 1 × 1 0 − 2 2.303 lo g 10 5 20 ∴ t = 2.303 × 0.602 × 1 0 2 = 138.6 s

Chemistry - Chemical Kinetics Question with Solution | TestHub

ChemistryChemical KineticsSecond & nth Order ReactionsEasy2 minPYQ_2020

ChemistryEasysingle choice

A first order reaction has rate constant $1 \times 1 0^{- 2} s^{- 1}$ . What time will it take for $20 g$ of reactant to reduce to $5 g$ ?

Options:

Answer:

Solution:

(A) $k = 1 \times 1 0^{- 2} s^{- 1}, [A]_{0} = 20 g, [A]_{t} = 5 g$ For first order reaction, $t = \frac{2.303}{k} lo g_{10} \frac{[ A ] _{0}}{[ A ] _{t}}$ $∴ t = \frac{2.303}{1 \times 1 0 ^{- 2}} lo g_{10} \frac{20}{5}$ $∴ t = 2.303 \times 0.602 \times 1 0^{2} = 138.6 s$

Stream:MHT_CETSubject:ChemistryTopic:Chemical KineticsSubtopic:Second & nth Order Reactions

⏱ 2mℹ️ Source: PYQ_2020

Doubts & Discussion

Loading discussions...