Mechanism for NO2 + CO -> NO + CO2: slow 2NO2 -> NO3 + NO with step rate = k[NO2]^2, k = 0.50 M^-1 s^-1; fast NO3 + CO -> NO2 + CO2. At [NO2] = 0.20 M and [CO] = 0.50 M, the net rate of consumption of NO2 in the overall reaction, in M s^-1, is

JEE Advanced levelSingle correct optionDifficulty 3 of 3ck173

Mechanism for $NO X_{2} + CO NO + CO X_{2}$ : slow $2 NO X_{2} NO X_{3} + NO$ with step rate $= k [NO X_{2}]^{2}$ , $k = 0.50 M^{- 1} s^{- 1}$ ; fast $NO X_{3} + CO NO X_{2} + CO X_{2}$ . At $[NO X_{2}] = 0.20 M$ and $[CO] = 0.50 M$ , the net rate of consumption of $NO X_{2}$ in the overall reaction, in $M s^{- 1}$ , is

Each slow event has rate

k [NO X_{2}]^{2} = 0.50 \times 0.2 0^{2} = 0.020 M s^{- 1}

and uses

2

NO X_{2}

, but the fast step returns

1

, so net consumption is

1

per event:

0.020 M s^{- 1}

. This matches the overall equation (coefficient of

NO X_{2}

1

); the CO concentration does not enter.