Easy INTEGER +4 / -1 PYQ · JEE Mains 2021

${N_2}{O_{5(g)}} \to 2N{O_{2(g)}} + {1 \over 2}{O_{2(g)}}$

In the above first order reaction the initial concentration of N2O5 is 2.40 $\times$ 10$-$2 mol L$-$1 at 318 K. The concentration of N2O5 after 1 hour was 1.60 $\times$ 10$-$2 mol L$-$1. The rate constant of the reaction at 318 K is ______________ $\times$ 10$-$3 min$-$1. (Nearest integer)

[Given : log 3 = 0.477, log 5 = 0.699]

Answer (integer) 7

Solution

$K = {{2.303} \over t}\log {{{{[{N_2}{O_5}]}_0}} \over {{{[{N_2}{O_5}]}_t}}}$<br><br>$= {{2.303} \over {60}}\log {{2.4} \over {1.6}} = 6.76 \times {10^{ - 3}}$ min<sup>$-$1</sup> $\approx$ 7 $\times$ 10<sup>$-$3</sup> min<sup>$-$1</sup>

About this question

Subject: Chemistry · Chapter: Chemical Kinetics · Topic: Rate of Reaction

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