Potassium dichromate `(K_(2)Cr_(2)O_(7))` is an orange coloured compound, very frequently used in laboratory as an oxidising agent as well as in a redox titration. It is generally prepared from chromit `(FeCr_(2)O_(4))` ore according to the following reactions: (a) Fusion of chromite ore with sodium carbonate in excess of air. `FeCr_(2)O_(4)+Na_(2)CO_(3)+O_(2) to Na_(2)CrO_(4)+Fe_(2)O_(3)+CO_(2)` (b) Acidifying filetered sodium chromate solution with sulphuric acid. `Na_(2)CrO_(4)+H_(2)SO_(4) to Na_(2)Cr_(2)O_(7)+Na_(2)SO_(4)+H_(2)O` (c) Treating sodium dichromate with potassium chloride. `Na_(2)Cr_(2)O_(7)+KCl to K_(2)Cr_(2)O_(7)+NaCl` Answer the following questions using above information. If you are intially provided with 224 gm of pure chromite ore and 169.6gm of sodium carbonate, the minimum volume of air required at 1 atm and 273 K to consume at least one of the reactant completely, if aire contains 20% by volume of oxygen gas is :A. 156.8LB. 196LC. 28LD. 152.4L

Potassium dichromate `(K_(2)Cr_(2)O_(7))` is an orange coloured compou

1.	Potassium dichromate `(K_(2)Cr_(2)O_(7))` is an orange coloured compound, very frequently used in laboratory as an oxidising agent as well as in a redox titration. It is generally prepared from chromit `(FeCr_(2)O_(4))` ore according to the following reactions: (a) Fusion of chromite ore with sodium carbonate in excess of air. `FeCr_(2)O_(4)+Na_(2)CO_(3)+O_(2) to Na_(2)CrO_(4)+Fe_(2)O_(3)+CO_(2)` (b) Acidifying filetered sodium chromate solution with sulphuric acid. `Na_(2)CrO_(4)+H_(2)SO_(4) to Na_(2)Cr_(2)O_(7)+Na_(2)SO_(4)+H_(2)O` (c) Treating sodium dichromate with potassium chloride. `Na_(2)Cr_(2)O_(7)+KCl to K_(2)Cr_(2)O_(7)+NaCl` Answer the following questions using above information. If you are intially provided with 224 gm of pure chromite ore and 169.6gm of sodium carbonate, the minimum volume of air required at 1 atm and 273 K to consume at least one of the reactant completely, if aire contains 20% by volume of oxygen gas is :A. 156.8LB. 196LC. 28LD. 152.4L
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`0.80 g` of sample of impure potassium dichromate was dissolved in water and made up to `500 mL` solution. `25 mL` of this solution treated with excess of `KI` in acidic medium and `I_(2)` liberated required `24 mL` of a sodium thiosulphate solution. `30 mL` of this sodium thiosulphate solution required `15 mL` of `N//20` solution of pure potassium dichromate. What was the percentage of `K_(2)Cr_(2)O_(7)` in given sample?A. `73.5%`B. `75.3%`C. `36.75%`D. none of these
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