For A ->[k_1] B ->[k_2] C with k_1 = 5.0x10^-2 s^-1 and k_2 = 2.0x10^-4 s^-1, the rate at which C appears after the initial period is governed mainly by

k_2, the smaller rate constant (slow step)

JEE Main levelSingle correct optionDifficulty 2 of 3ck210

For $A k X_{1} B k X_{2} C$ with $k_{1} = 5.0 \times 1 0^{- 2} s^{- 1}$ and $k_{2} = 2.0 \times 1 0^{- 4} s^{- 1}$ , the rate at which C appears after the initial period is governed mainly by

In consecutive reactions, the overall formation of the final product is limited by the slower step. Here

k_{2} = 2.0 \times 1 0^{- 4}

is much smaller than

k_{1} = 5.0 \times 1 0^{- 2}

, so B accumulates and C forms at a rate set by

k_{2} [B]