A sample containing `HAsO_2` (mol. mass `=108`) and weighing `3.78g` is dissolved and diluted to `250mL` in a volumetric flask. `A 50mL` sample (aliquat) is withdrawn with a pipet and titrated with `35mL` of `0.05 M` solution of `I_2`.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 A 50 mL sample (aliquot) is withdrawn with a pipet and titrated with 25 mL of 0.05 M solution of I_(2) .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 :

A sample of NaNO_(3) weighing 0.38 g is placed in a 50.0 mL volumetric flask. The flask is then filled with water to the mark on the neck. What is the molarity of the solution?

50.0 g sample of brass is dissolved in 1 L dil H_2SO_4.20mL of this solution is mixed with KI, and the liberated I_2 required 20 " mL of " 0.5 M hypo solution for titration calculate the amount of Cu in the alloy.

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) .

150 mL of N/10 HCI are required to react completely with 1.0 g of a sample of lime stone ( CaCO_3 ). Calculate the percentage purity of the sample.

5g sample contain only Na_2CO_3 and Na_2SO_4 . This sample is dissolved and the volume made up to 250mL. 25mL of this solution neutralizes 20mL of 0.1M H_2SO_4 . Calculate the percent of Na_2SO_4 in the sample.

1.249 g of a sample of pure BaCO_(3). and impure CaCO_(3) containing some CaO was treated with dil . HCl and it evoled 168 ml of CO_(2) at NTP . From this solution , BaCrO_(4) was precipitated , filtered and washed . The precipitate was dissolved in dilute sulphauric acid and diluted to 100 ml. 10 ml of this solution , when treated with Kl solution , liberated iodine which required exactly 20 ml of 0.05 ml of 0.05 N Na_(2)S_(2)O_(3) . Calculate the percentage of CaO in the sample.

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.)

0.10 g of a sample containing CuCO_(3) and some inert impurity was dissolved in dilute sulphuric acid and volume made up to 520 mL. This solution was added into 50mL of 0.04 M KI solution where copper precipitates as Cul and I^(-) is oxidized into I_(3)^(-) . A 10 mL portion of this solution is taken for analysis, filtered and made up free I_(3)^(-) and then treated with excess of acidic permanganate solution. Liberated iodine required 20 mL of 2.5 mM sodium thiosulphate solution to reach the end point. Determine mass percentage of CuCO_(3) in the original sample.

A 20.0 mL sample of a 0.20 M solution of the weak diprotic acid H_(2)A is titrated with 0.250 M NaOH. The concentration of solution at the second equivalent point is: