How might a compound be zero-order?

Im confused to exactly why a compound might be zero-order in a reaction. Like what makes it have no influence on the rate of reaction? for my experiment I studied potassium permanganate and oxalic acid and found permanganate was a zero-order and had no influence on the rate of reaction. Why might this be? I thought maybe because oxalic is in excess but I'm not too sure. Any help would be good!

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  • Mike A
    Lv 7
    1 month ago

    It usually means that the overall reaction proceeds in multiple steps and you have a rapid first step followed by a much slower step leading to the product(s).

    A <====> A*  (Rapidly established equilibrium)

    A* +  B --------------> Products (slow)

    The rate will be;- k[A*][B]

    But [A*] will be constant until most of the A is used up, 

    so you can rewrite the rate as:- k'[B] where k' = k[A*]

    Other examples can be found here:

    https://chem.libretexts.org/Bookshelves/Physical_a...

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