A sample of pyrolusite `(MnO_2)` weighs 0.5 g. To its solution, 0.6674 g of `As_2O_3` and dilute, acid are added. After the reaction has ceased, arsenic `(As^(3+))` in `As_2O_3` is titrated with `45mL` of `(M)/(50)` `KMnO_4` solution. Calculate the percentage of `MnO_2` in pyrolusite. (Atomic weight of As is 74.9 and that of Mn is 55.)

A sample of pynolusite (MnO_(2)) weights 0.5 gm. To this solutioin 0.594 gm As_(2)O_(3) and a dilute acid are added. After the reaction has stopped As^(+3) is AS_(2)O_(3) is titrated with 45 mlof M/50 KMn_(4) solution. Calculate the percentage of MnO_(2) in pyrolusite.

0.804 g sample of iron was dissolved in acid , Iron was reduced to +2 state and it required 47.2 mL of 0.112 N KMnO_4 solution for titration. Calculate the percentage of iron and Fe_3O_4 in the ore.

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

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

A sample containing HAsO_(2) (mol. Mass=108) and weighing 3.78 g is dissolved and diluted to 250 mL in a volumetric flask. A 50 mL sample (aliquot) is withdrawn with a pipet and titrated with 25 mL of 0.05 M solution of I_(2) . Calculate the percentage HAsO_(2) in the sample :

A sample containing HAsO_(2) (mol. Mass=108) and weighing 3.78 g is dissolved and diluted to 250 mL in a volumetric flask. A 50 mL sample (aliquot) is withdrawn with a pipet and titrated with 25 mL of 0.05 M solution of I_(2) . Calculate the percentage HAsO_(2) in the sample :

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) .