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

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,
${\text{3Ba}}{{\text{O}}_{\text{2}}}{\text{.8}}{{\text{H}}_{\text{2}}}{\text{O + 2}}{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}} \to {\text{B}}{{\text{a}}_{\text{3}}}{{\text{(P}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 3}}{{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}$