What do we evaluate and conclude based on the surface area of rhubarb?

Rhubarb is a plant whose sticks contain oxalic acid. It is often used in a chemistry laboratory experiment to decolorize potassium permanganate solution. The sticks of rhubarb contain oxalic acid, which on reaction with potassium permanganate solution, reduces it and causes a color change from purple to colorless.

In this experiment, we evaluate the effect of surface area of rhubarb sticks on the rate of decolorization of potassium permanganate solution. We can use sticks of different sizes and mix them with the same volume (say 250 ml) of potassium permanganate solution. In each case, we can observe how fast the solution loses color. Based on our observations, we can conclude that increasing the surface area of rhubarb (which will increase the quantity of oxalic acid that is available to reduce the potassium permanganate) will increase the rate of decoloration of potassium permanganate solution.

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