Question

upon addition of the hydrogen peroxide, you should observe the reaction colour shift quickly to a yellow/orange colour. what substance is responsible for this colour? why does the colour fade as the reflux progresses?

Answer 1

The yellow/orange color observed after adding hydrogen peroxide in the presence of manganese dioxide is due to an intermediate in the decomposition reaction. This color fades as the reaction proceeds because the intermediate breaks down into colorless products. The addition of a catalyst like manganese dioxide greatly accelerates the decomposition of hydrogen peroxide.

Step-by-step explanation:

The yellow/orange color observed upon the addition of hydrogen peroxide is typically the result of an intermediate compound formed during the decomposition of hydrogen peroxide. When hydrogen peroxide is added to manganese dioxide, it decomposes rapidly to form oxygen and water. This reaction is catalyzed by the manganese dioxide.

The color fades as the reflux progresses because the intermediate responsible for the color is transient and decomposes into colorless products such as water and oxygen gas. Therefore, as the reaction proceeds and more peroxide is broken down, the concentration of the colored intermediate decreases, leading to a fading color.

In general, the presence of a catalyst like manganese dioxide increases the rate at which hydrogen peroxide decomposes by providing an alternative pathway or mechanism for the reaction to follow, without being consumed in the process. This is why the reaction is much faster, and you can observe gas bubbling in the test tube, and why in the absence of a catalyst, decomposition of hydrogen peroxide is very slow.