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Standard XII

Chemistry

First Order Reaction

In a first-or...

Question

In a first-order reaction the concentration of the reactant is decreased from $1.0 M to 0 .25 M$ in 20 min.The rate constant of the reaction would be:

10 mi n^{- 1}

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6.931 mi n^{- 1}

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0.6931 mi n^{- 1}

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0.06931 mi n^{- 1}

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Solution

The correct option is D $0.06931 mi n^{- 1}$
Its First Order Reaction

$k = \frac{2.303}{t} l o g \frac{[A]}{[A - x]}$

Substituting the values,

$k = \frac{2.303}{20} l o g \frac{[1]}{[0.25]}$
$k = 0.06931 {m i n}^{- 1}$

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In a first-order reaction the concentration of the reactant is decreased from 1.0 M to 0.25 M in 20 min.The rate constant of the reaction would be:

The correct option is D 0.06931 min−1Its First Order Reactionk=2.303tlog [A][A−x]Substituting the values,k=2.30320log [1][0.25]k=0.06931 min−1

In a first-order reaction the concentration of the reactant is decreased from $1.0 M to 0 .25 M$ in 20 min.The rate constant of the reaction would be:

The correct option is D $0.06931 mi n^{- 1}$
Its First Order Reaction

$k = \frac{2.303}{t} l o g \frac{[A]}{[A - x]}$

Substituting the values,

$k = \frac{2.303}{20} l o g \frac{[1]}{[0.25]}$
$k = 0.06931 {m i n}^{- 1}$