# Chemistry doubt

$0.5\text{ g}$ sample of a sulphite salt was dissolved in $200\text{ ml}$ and $20\text{ ml}$ of this solution required $10\text{ ml}$ of $0.02\text{ M}$ acidified permanganate solution.Find the percentage by mass of sulphite in sulphite ore?

Please help! Note by Shivam Mishra
4 years, 10 months ago

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## Comments

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- 4 years, 7 months ago

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Thanks @Utkarsh Dwivedi

- 4 years, 9 months ago

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My solution :

Let the number of moles of sulphite ions be $M$. Clearly on oxidation the sulphite ion changes to sulphate so the oxidation number changes from $4+$ to $6+$, hence the valence factor is $2$. The product of moles and valence factor gives the equivalents. The valence factor permagnate solution in acidified solution is $5$. Equate the equivalents as :

$M ×2×\frac{20}{200} = \frac{10}{1000} × 0.02 × 5$

$M=\frac{5}{1000}$

As molecular weight of sulphite ion is $80$, percentage by mass is :

$\frac{0.005 × 80}{0.5} × 100$ $=80 \%$

- 4 years, 9 months ago

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Tell me is this question based on molarity

- 4 years, 9 months ago

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Yes,but it can also be solved using milliequivalents.

- 4 years, 9 months ago

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Is the information complete?

- 4 years, 10 months ago

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Yes

- 4 years, 10 months ago

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@Deeparaj Bhat @Prakhar Bindal please help!!!!

- 4 years, 10 months ago

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