Home
Class 12
CHEMISTRY
0.6 g of a sample of pyrolusite was boil...

0.6 g of a sample of pyrolusite was boiled with 200 " mL of " `(N)/(10)` oxalic acid and excess of dilute sulphuric acid. The liquid was filtered and the residue washed. The filtrate and washing were mixed and made up to 500 mL in a measuring flask. 100 " mL of " this solution required 50 " mL of " `(N)/(30)KMnO_4` solution. Calculate the percentage of `MnO_2` in the sample `(Mn=55)`.

Text Solution

Verified by Experts

Redox changes are
`C_(2)O_(4)^(-2) to 2CO_(2) ` (n-factpr = 2)
`MnO_(4)^(-) to Mn^(2+) ` (n-factor = 5)
`MnO_(2) to Mn^(2+)` (n-factor = 2)
Meq. Of `MnO_(2) ` = Meq. Of oxalic acid taken - Meq. Of oxalic acid left
` = 50 xx 0.5 xx 2 - 32 xx 0.02 xx 5 xx 10 ` (in 250 ml) = 18
`W_(MnO_(2))/M_(MnO_(2)) xx 2 xx 1000 = 18 rArr W_(MnO_(2))/87 xx 2 xx 1000 = 18 `,
`:. W_(MnO_(2)) = 0.7821 ` gm
` :. % " of " MnO_(2) = (0.7821)/ (1.6) xx 100 = 48.88 %`
Meq. of `MnO_(2)` = Meq. of `O_(2) `
`W_(O_(2)) /16 xx 2 xx 1000 = 18, :. w_(o_(2)) = 0.144` g
% of available `O_(2) = (0.144)/(1.6) xx 100 = 9 `
Promotional Banner

Similar Questions

Explore conceptually related problems

1.5 g of chalk was treated with 10 " mL of " 4 N HCl. The chalk was dissolved and the solution was made to 100 mL. 25 " mL of " this solution required 18.75 " mL of " 0.2 N NaOH solution for comjplete neutralisation. Calculate the percentage of pure CaCO_3 in the sample of chalk.

4.0 g of a mixture of Nacl and Na_(2) CO_(3) was dissolved in water and volume made up to 250 mL . 25 mL of this solution required 50 mL of N//10 HCl for complete neutralisation. Calculate the percentage composition of the original mixture.

10.875 g of a mixture of NaCI and Na_2CO_3 was dissolved in water and the volume was made up to 250 mL. 20.0 mL of this solution required 75.5 mL of N/10 H_2SO_4 . Find out the percentage composition of the mixture.

A sample of sodium carbonate contains impurity of sodium sulphate. 1.25 g of this sample are dissolved in water and volume made up to 250 mL. 25 mL of this solution neutralise 20 mL of N/10 sulphuric acid. Calculate the percentage of sodium carbonate in the sample.

10 g of oxalate was dissolved in 300 mL of solution. This solution required 250 mL of (M/10)KMnO_(4) in acidic medium for complete oxidation. The percentage purity of oxalate ion in the salt is :

0.2828 g of iron wire was dissolved in excess dilute H_(2)SO_(4) and the solution was made upto 100mL. 20mL of this solution required 30mL of N/(30)K_(2)Cr_(2)O_(7) solution for exact oxidation. Calculate percent purity of Fe in wire.

0.2 g if a sample of H_2 O_2 required 10 ml of 1 N KMnO_4 for titration in acidic medium. The percentage purity of H_2 O_2 sample is:

500 ml of 2M NaCl solution was mixed with 200 ml of 2 M NaCl solution. Calculate the molarity of NaCl in final solution

0.7 g sample of iron ore was dissolved in acid. Iron was reduced to +2 state and it required 50 " mL of " (M)/(50) KMnO_(4) solution for titration. The percentage of Fe and Fe_(3)O_(4) in the ore is

1.26 g of a dibasic acid were dissolved in water and the solution made up to 200 mL. 20 mL of this solution were completely neutralised by 10 mL of N/5 NaOH solution. Calculate the equivalent mass and molecular mass of the acid.