Question

Hydrogen peroxide is prepared in the laboratory by :
\[{\text{(A)}}\] Adding \[{\text{Mn}}{{\text{O}}_{\text{2}}}\] to dilute \[{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}\]
\[{\text{(B)}}\]Passing \[{\text{C}}{{\text{O}}_{\text{2}}}\] into \[{\text{Ba}}{{\text{O}}_{\text{2}}}\] paste in cold water
\[{\text{(C)}}\]Adding \[{\text{Pb}}{{\text{O}}_{\text{2}}}\] to an acidified \[{\text{KMn}}{{\text{O}}_{\text{4}}}\] solution
\[{\text{(D)}}\]Adding \[{\text{N}}{{\text{a}}_{\text{2}}}{{\text{O}}_{\text{2}}}\] to cold water

Answer 1

Hint:Hydrogen peroxide is an oxidizing agent useful for synthetic purposes and also catalyze many reactions. it may be prepared from following methods:
1.From barium peroxide
2.From electrolytic process
3.From non-electrolytic process.

Complete step by step answer:
Preparation of hydrogen peroxide \[{\text{(}}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}})\]:
We can prepare hydrogen peroxide by the action of \[{\text{C}}{{\text{O}}_{\text{2}}}\] on Barium peroxide. Here we use a thick icy paste of barium hydroxide by putting in some ice cold water and we pass \[{\text{C}}{{\text{O}}_{\text{2}}}\] to the thick icy paste of barium hydroxide. Now \[{\text{C}}{{\text{O}}_{\text{2}}}\] on reaction with water is generates carbonic acid \[{\text{(}}{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}{\text{)}}\] and then \[{\text{Ba}}{{\text{O}}_{\text{2}}}\] reacts with \[{{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}\] to form barium carbonate and it is obtained as a white precipitate which can be removed by filtration, hydrogen peroxide is left behind as a byproduct.
\[{\text{Ba}}{{\text{O}}_{\text{2}}}{\text{ + C}}{{\text{O}}_{\text{2}}}{\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}} \to {\text{BaC}}{{\text{O}}_{\text{3}}}{\text{ + }}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}\]
Therefore, the correct answer is option \[{\text{(B)}}\].

Additional information:
Hydrogen peroxide can be prepared by the action of sulphuric acid or phosphoric acid on hydrated barium peroxide \[{\text{Ba}}{{\text{O}}_{\text{2}}}{\text{.8}}{{\text{H}}_{\text{2}}}{\text{O}}\].
\[{\text{Ba}}{{\text{O}}_{\text{2}}}{\text{.8}}{{\text{H}}_{\text{2}}}{\text{O (s) + }}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{(aq)}} \to {\text{BaS}}{{\text{O}}_{\text{4}}}{\text{(s) + }}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}{\text{(aq) + 8}}{{\text{H}}_{\text{2}}}{\text{O (l)}}\]
Anhydrous barium peroxide do not readily react with \[{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}\] as a coating of the insoluble barium sulphate is generated on its surface that further stops action of the acid. Therefore, hydrated barium peroxide i.e. \[{\text{Ba}}{{\text{O}}_{\text{2}}}{\text{.8}}{{\text{H}}_{\text{2}}}{\text{O}}\] should be used . The product of the barium sulphate is obtained in the form of white precipitate so that it become easy for us for filtering out the precipitate and the we get a solution of \[{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}\].

Note:
Hydrogen peroxide prepared from barium peroxide and sulfuric acid can't be used for a longer duration of time or can’t be stored for a long time. So what we do is instead of using sulphuric acid we use phosphoric acid. The reaction can be given as,
\[{\text{3Ba}}{{\text{O}}_{\text{2}}}{\text{.8}}{{\text{H}}_{\text{2}}}{\text{O + 2}}{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}} \to {\text{B}}{{\text{a}}_{\text{3}}}{{\text{(P}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 3}}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}\]