What is equivalent weight of H2O2 in decomposition reaction?

1 Answer
Jun 12, 2018

Answer:

The equivalent weight of #"H"_2"O"_2# is 34.01 g.

Explanation:

The equivalent weight is the molecular weight (#"MM"#) divided by the number of electrons transferred per mole of reactant (#n#).

#color(blue)(bar(ul(|color(white)(a/a)"Equivalent weight" = "MM"/ncolor(white)(a/a)|)))" "#

We need the moles of electrons, so let's balance the equation by the ion-electron method.

Unbalanced equation: #"H"_2"O"_2 → "H"_2"O" + "O"_2#

Reduction: #1 × ["H"_2"O"_2 + "2H"^"+" + 2"e"^"-"→ "2H"_2"O" ]#
Oxidation: #1 × ul(["H"_2"O"_2 → "O"_2 + "2H"^"+" + "2e"^"-"]color(white)(mm))#
Overall: #color(white)(mmmm)2"H"_2"O"_2 → "O"_2 + "2H"_2"O"#

We see that the reaction involves the transfer of 2 mol of electrons.

Since the reaction also involves 2 mol of #"H"_2"O"_2#, the number of electrons transferred per mole of #"H"_2"O"_2# is

#n = ("2 mol e"^"-")/("2 mol H"_2"O"_2) = 1color(white)(l) "mol electrons per mole of H"_2"O"_2"#

#"Equivalent weight" = "MM"/n = "34.01 g"/1 = "34.01 g"#

The equivalent weight of #"H"_2"O"_2# in this reaction is 34.01 g.