Question

Most hydrogen peroxide bottles advertise that they contain 3% H2O2. What did you find in your experiment?
a)This cannot be determined via the methods here.
b) New H2O2 solution does indeed contain 3% H2O2
c) New H2O2 solution contains more than 3% H2O2
d) New H2O2 solutions contains less than 3% H2O2

Answer 1

Answer on Question #82660 – Chemistry – General Chemistry

Most hydrogen peroxide bottles advertise that they contain $3\%$ $\mathrm{H}_2\mathrm{O}_2$. What did you find in your experiment?

a) This cannot be determined via the methods here

b) New $\mathrm{H}_2\mathrm{O}_2$ solution does indeed contain $3\%$ $\mathrm{H}_2\mathrm{O}_2$

c) New $\mathrm{H}_2\mathrm{O}_2$ solution contains more than $3\%$ $\mathrm{H}_2\mathrm{O}_2$

d) New $\mathrm{H}_2\mathrm{O}_2$ solutions contains less than $3\%$ $\mathrm{H}_2\mathrm{O}_2$

Solution:

Concentration of $\mathrm{H}_2\mathrm{O}_2$ by mass = 3.0 g of $\mathrm{H}_2\mathrm{O}_2$ in 100 g (100 mL) of solution

$$n(\mathrm{H}_2\mathrm{O}_2) = 3.0 \, \mathrm{g} / 34.01 \, \mathrm{g/mol} = 0.088 \, \mathrm{mol}$$ $$2\mathrm{KMnO}_4 + 5\mathrm{H}_2\mathrm{O}_2 + 3\mathrm{H}_2\mathrm{SO}_4 \rightarrow \mathrm{K}_2\mathrm{SO}_4 + 2\mathrm{MnSO}_4 + 8\mathrm{H}_2\mathrm{O} + 5\mathrm{O}_2$$ $$n(\mathrm{KMnO}_4) = 2 \, \mathrm{mol}; \, n(\mathrm{H}_2\mathrm{O}_2) = 5 \, \mathrm{mol}$$ $$n(\mathrm{KMnO}_4) = C(\mathrm{KMnO}_4) \times V(\mathrm{KMnO}_4)$$

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