The ordinary macro-Kjeldahl method was much improved in speed and reliability by using a mixed selenium–mercury catalyst with the usual potassium sulphate; but even in this case some doubt ...

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After one hour, equilibrium has been reached which means the potassium permanganate crystals are at an equal concentration throughout the water. Diffusion has stopped.

Convection in a liquid Convection in a liquid can be seen by putting a crystal of potassium permanganate in a beaker of water and gently heating it with a Bunsen flame. Air current close to a ...