step 1: ce^{4 +}+mn^{2 +}\to ce^{3 +}+mn^{3 +}\nstep 2: ce^{4 +}+mn^{3 +}\to ce^{3 +}+mn^{4 +}\nstep 3…

step 1: ce^{4 +}+mn^{2 +}\to ce^{3 +}+mn^{3 +}\nstep 2: ce^{4 +}+mn^{3 +}\to ce^{3 +}+mn^{4 +}\nstep 3: mn^{4 +}+tl^{+}\to tl^{3 +}+mn^{2 +}\nthe proposed steps for a catalyzed reaction between ce^{4 +} and tl^{+} are represented above. the catalyst(s) in this reaction is/are\na ce^{4 +}\nb mn^{2 +}\nc mn^{2 +} and mn^{3 +}\nd tl^{3 +}

step 1: ce^{4 +}+mn^{2 +}\to ce^{3 +}+mn^{3 +}\nstep 2: ce^{4 +}+mn^{3 +}\to ce^{3 +}+mn^{4 +}\nstep 3: mn^{4 +}+tl^{+}\to tl^{3 +}+mn^{2 +}\nthe proposed steps for a catalyzed reaction between ce^{4 +} and tl^{+} are represented above. the catalyst(s) in this reaction is/are\na ce^{4 +}\nb mn^{2 +}\nc mn^{2 +} and mn^{3 +}\nd tl^{3 +}

Answer

Explanation:

Step1: Recall catalyst definition

A catalyst is a substance that is consumed in an early - step of a reaction mechanism and regenerated in a later step.

Step2: Analyze the reaction steps

In step 1, $\text{Mn}^{2 + }$ is consumed when it reacts with $\text{Ce}^{4+}$. In step 3, $\text{Mn}^{2+}$ is regenerated when $\text{Mn}^{4 + }$ reacts with $\text{Tl}^{+}$.

Answer:

B. $\text{Mn}^{2+}$