Question

The rate of decomposition of hydrogen peroxide can be slowed down through
A. Glycerin
B. Manganese oxide
C. Vanadium oxide
D. Platinum

Answer 1

Hint: To solve this question we must know a few basic concepts of hydrogen peroxide. Hydrogen peroxide is the simplest kind of peroxide which is available. It is a colourless liquid which is used in aqueous solution for safety reasons. It acts as a bleaching agent and is also used as a disinfectant. The structure of hydrogen peroxide is non-planar. It has an open book structure with \[O{\text{ }}-{\text{ }}O\]s pins.

Complete step by step answer:
Hydrogen peroxide in its pure form exists in a very pale blue liquid which is slightly more viscous than water. Since it is unstable it slowly decomposes in the presence of light and it is stored with a stabilizer in a weakly acidic solution in dark-coloured bottles. The rate of decomposition can be increased with the increase in temperature, concentration as well as $pH$.
In the process of decomposition of hydrogen peroxide, it is broken down to water and oxygen. The decomposition of ${H_2}{O_2}$ is slowed down in the presence of glycerin and alcohol. In order to prevent the decomposition hydrogen peroxide is stored in paraffin wax coated plastic or Teflon bottles. Small amount of glycerol, alcohol, acetamide, acid and phosphoric acid are usually used as stabilizers in order to check the decomposition.
Glycerin affects the rate of decomposition of hydrogen peroxide and slows down the reaction, therefore it is called the negative catalyst.

So, the correct answer is Option A.

Note: We must remember that a positive catalyst will speed up the reaction whereas a negative catalyst will decrease the rate or speed of a reaction. In the case of decomposition of hydrogen peroxide, potassium iodide or compounds of transition metals will be positive catalysts whereas glycerin will be a negative catalyst.