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. 7.41B. 74.1C. 61.75D. None of these

0.10 g of a sample containing `CuCO_(3)` and some inert impurity was d

1.	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. 7.41B. 74.1C. 61.75D. None of these
Answer» Correct Answer - B

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The purity of `H_2O_2` in a given sample is `85%.` Calculate the weight of impure sample of `H_2O_2` which requires `10mL` of `M//5 KMnO_4` solution in a titration in acidic mediumA. 2 gB. 0.2 gC. 0.17 gD. 0.15 g
An impure sample of sodium oxalate `(Na_(2)C_(2)O_(4)` weighing 0.20 g is dissolved in aqueous solution of `H_(2)SO_94)` and solution is titrated at `70^(@)C`,requiring 45 mL of 0.02 M `KMnO_(4)` solution. The end point is overrun, and back titration in carried out with 10 mL of 0.1 M oxalic acid solution.Find the purity of `Na_(2)C_(2)O_(4)` in sample:A. 75B. 83.75C. 90.25D. None of these
`60ml` of mixture of equal volumes of `Cl_(2)` and an oxide of chloine, i.e., `Cl_(2)O_(n)` was heated and then cooled back to the original temperature. The resulting gas mixture was found to have volume of `75ml`. On treatment with `KOH` solution, the volume contracted to `15ml`. Assume that all measurements are made at the same temperature and pressure. Deduce the value of `n` in `Cl_(2)O_(n)`. The oxide of `Cl_(2)` n heating decomposes quantiatively to `O_(2)` and `Cl_(2)`.
`12. g` of an impure sample of arsenious oxide was dissolved in water containing `7.5 g` of sodium bicarbonate and the resulting solution was diluted to `250 mL`. `25 mL` of this solution was completely oxidised by `22.4 mL` of a solution of iodine. `25 mL` of this iodine solution reacted with same volume of a solution containing `24.8 g` of sodium thiosulphate `(Na_(2)S_(2)O_(3).5H_(2)O)` in one litre. Calculate teh percentage of arsenious oxide in the sample ( Atomic mass of `As=74`)
`K_(2)Cr_(2)O_(7)` is obtained in the following steps: `2FeCrO_(4)+2Na_(2)CO_(3)+OtoFe_(2)O_(3)+2Na_(2)CrO_(4)+2CO_(2)` `2Na_(2)CrO_(4)+H_(2)SO_(4)toNa_(2)Cr_(2)O_(7)+H_(2)O+Na_(2)SO_(4)` `Na_(2)Cr_(2)O_(7)+2KCltoK_(2)Cr_(2)+2NaCl` To get 0.25 " mol of "`K_(2)Cr_(2)O_(7)`, " mol of "`50%` pure `FeCrO_(4)` required.A. 1 molB. 0.50 molC. 0.25 molD. 0.125 mol
How many moles of `O_(2)` will be liberated by one mole of `CrO_(5)` is the following reaction: `CrO_(5) + H_(2) SO_(4) rarr Cr_(2) (SO_(4))_(3) + H_(2)O + O_(2)`A. `(5)/(2)`B. `(5)/(4)`C. `(9)/(2)`D. none of these
A sample containing 0.4775 of `(NH_(4))_(2)C_(2)O_(4)` and inert material was dissolved in water and made strongly alkaline with KOH which converted `NH_(4)^(o+)` to `NH_(3)` The liberated `NH_(3)` was distilled of `H_(2)SO_(4)` was back titrated with 11.3 " mL of " 0.1214 M NaOH. Calculate (a) `% of (NH_(4))_(2)C_(2)O_(4)=124.10` And atomic weight of `N=14.0078`.
2.0 g sample of NaCN is dissolved in 50 " mL of " 0.3 M mild alkaline `KMnO_(4)` and heated strongly to convert all the `CN^(ɵ)` to `OCN^(ɵ)`. The solution after acidification with `H_(2)SO_(4)` requries 500 " mL of " 0.05 M `FeSO_(4)` Calculate the percentage purity of NaCN in the sample.
10 " mL of " `NaHC_(2)O_(4)` is oxidised by 10 " mL of " 0.02 M `MnO_(4)^(ɵ)`. Hence, 10 " mL of " `NaHC_(2)O_(4)` is neutralised byA. 10 " mL of " 0.1 M NaOHB. 10 " mL of " 0.02 M NaOHC. 10 " mL of " 0.1 M `Ca(OH)_(2)`D. 10 " mL of " 0.05 N `Ba(OH)_(2)`
`CN^(ɵ)` is oxidised by a strong oxidising agent to `NO_3^(ɵ)` and `CO_2` or `CO_3^(2-)` depending upon the acidity of the reaction mixture. `HNO_3` a strong oxidising agent is reduced by a moderate reducing agent to NO. Write the balanced equation of `HNO_3` with KCN. `CH^(ɵ)toCO_2+NO_3^(ɵ)` `NO_3^(ɵ)NO` If this reaction is carried out, what safety precautions are required?

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