Question

The reaction $ 2{{H}_{2}}{{O}_{2}}\xrightarrow{{}}2{{H}_{2}}O+{{O}_{2}} $ is:

• A. a redox reaction
• B. a hydrolysis reaction
• C. a solvolysis reaction
• D. an oscillatory reaction
• E. disproportionation

Answer 1

Answer: (E)

$ \underset{+1-1}{\mathop{{{H}_{2}}{{O}_{2}}}}\,+\underset{+1-1}{\mathop{{{H}_{2}}{{O}_{2}}}}\,\xrightarrow{{}}2\underset{+1-2}{\mathop{{{H}_{2}}O}}\,+\underset{0}{\mathop{{{O}_{2}}}}\, $ Here the oxidation number of hydrogen is not changed while the oxidation number of oxygen in $ {{H}_{2}}{{O}_{2}},{{H}_{2}}O $ and $ {{O}_{2}} $ is $ -1,-2 $ and 0. Hence, oxygen in undergoing oxidation to $ {{O}_{2}} $ ( $ -1 $ to 0) as well as reduction to $ {{H}_{2}}O(-1\text{ }to-2) $ . Such reactions where a molecule acts as both oxidising and reducing agent are called disproportionation.