Question

.Decomposition of hydrogen peroxide is retarded in the presence of :
A. Alcohol
B. Glycerin
C. Manganese oxide
D. Molybdenum

Answer 1

Hint: Decomposition reaction is a reaction that leads to breakdown of a compound into two or more components at least one of which must be in the elemental state. It is a type of redox reaction (that is one will observe a change in oxidation number of the interacting species).

Step by step answer:
Hydrogen peroxide decomposition reaction is a disproportionation reaction as hydrogen peroxide is simultaneously oxidized as well as reduced. The reaction happens as depicted below:

$2{H_2}{O_2}(l)\xrightarrow{{hv}}2{H_2}O(l) + {O_2}(g)$..

Hydrogen peroxide decomposes slowly on exposure to light as shown above. It is an unstable pale blue color liquid and decomposes due to auto reduction or auto oxidation on long standing or heating. The decomposition is further accelerated in the presence of metal surfaces such as cobalt , silver or molybdenum(Mo) or metal oxides such as manganese oxide($Mn{O_2}$).

Hence we can eliminate both option c and d. Since it is unstable and can even explode with the traces of organic matter or specs of dust. It is kept in wax lined glass or plastic vessels in the dark. Wax therefore retards the reaction and keeps hydrogen peroxide from decomposing.
Wax is an ester of glycerol and three fatty acids. Glycerin is a trihydroxy sugar alcohol colorless and odorless sweet liquid. Hence both option a and option b is correct and acts as a negative catalyst. Alcohol and glycerin keeps hydrogen peroxide from decomposing. Also as we know hydrogen peroxide is acidic in nature and adding an alcohol leads to neutralization reaction.

$2NaOH + {H_2}{O_2} \to N{a_2}{O_2} + 2{H_2}O$

The equation above is an example of adding alcohol and hydrogen peroxide. The products formed are sodium peroxide and water.

Hence the correct answer is (A) and (B).

Additional information:
Hydrogen peroxide has a non planar structure. It forms a dihedral angle of ${90.2^ \circ }$ in solid phase and ${111.5^ \circ }$ in gaseous phase. It has tremendous uses such as bleach, mild disinfectant and antiseptic.

Note: Multiple choice questions could have more than one correct answer make sure you check out all the options. Hydrogen peroxide can be manufactured by a lot of processes but it requires removal of last traces of water by freezing it in the mixture of dry ice and ether.