KCET 2025 Chemistry Paper

To determine the rate of production of NO2 for the reaction 2N2O5(g)⟶4NO2(g)+O2(g), we use the fact that the rate of production of a product is related to the rate of disappearance of a reactant.
Given:
Initial concentration of N2O5 is 2.0‌mol∕L.
After 300 minutes, the concentration is reduced to 1.4‌mol∕L.
Calculate the rate of disappearance of N2O5 :
Rate of disappearance of N2O5=‌

−(1.4−2.0)

300

=‌

−(−0.6)

300

=‌

0.6

300

As per the stoichiometry of the reaction, the rate of formation of NO2 is twice the rate of disappearance of N2O5 :
Rate of formation of NO2=2×‌

0.6

300

=‌

1.2

300

=4×10−3‌mol∕L∕min
Therefore, the rate of production of NO2 is 4×10−3‌mol∕L∕min.