How do you make the manganese dioxide pellets used for oxygen preparation please? The use of dilute hydrogen peroxide with the manganese dioxide powder produces a reaction thats often too vigorous and rapid.
One part manganese dioxide to three parts plaster of Paris.
Make a paste and leave it to dry over 2 days then break it into small pieces which fit the test tubes.
Or, you can role the paste into pellets of a size suitable for test tubes and let them dry.
Can be re-used.