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A solution of hydrogen peroxide, H2O2 , is titrated with potassium permanganate, KMnO4 , according to the following equation: 5 H2O2 2 KMnO4 3H2SO4 -> 5O2 2 MnSO4 8H2O K2SO4 It requires 46.9mL of 0.145 mol/L KMnO4 to titrate 50.0 mL of the solution of H2O2 . What is the moles per litre concentration of H2O2 in the solution?

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Answer:

concentration in mole per litre=0.34mol/L

Step-by-step explanation:

5H2O2 + 2KMnO4 + 3H2SO4 ----> 5O2 + 2MnSO4 + 8H2O + K2SO4

H2O2 gives Oxygen gas on oxidation

First calculate the n-factor to calculate the normality

write the oxidation number of oxidizing and reducing molecule both side:

product side:

Oxidizing molecule:

O=-1

reducing molecule:

Mn=+7

product side:

O=0;

Mn=+2

n-factor of H2O2=2×(0-(-1))=2

n-factor of H2O2=2;

n-factor of KMnO4=7-2=5

n-factor of KMnO4=5;

molarity of KMnO4 =0.145M

Normality=Molarity × n-factor

normality of KMnO4=0.145 ×5=0.725

normality of KMnO4=0.725

Volume of KMnO4=46.9 ml

Volume of H2O2=50 ml

Lets assume normality of H2O2=N

mili equivalent=volume in ml × normality

mili equivalent of H2O2=mili equivalent of KMnO4

N×50=0.725×46.9

N=0.68

concentration in mole per litre means molarity

molarity=normality/n-factor

molarity=0.68/2

molarity=0.34mol/L

concentration in mole per litre=0.34mol/L

User Alexandr Shapkin
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