Question
Q ONE LITRE MIXTURE OF CO &CO2 IS PASSED THRU RED HOT CHARCOAL IN A TUBE THE NEW VOL . BECOMES 1.2L WHAT % OF CO IN MIXTURE INITIALLY?
Q AN Aq SOLn CONTAINING 100 g OF DISSOLVED MgSO4 IS FED TO A CRYSTALLIZER WHERE 80% SALT CRY. OUT AS MgSO4.6H2O CRYSTAL HOW MANY gm OF HEXAHYDRATE SALT CRY. ARE OBTAINED FROM CRYSTALLIZER=?
ELECTROCHEM
Fe3+ + e- -----> Fe2+ = 0.77V
Fe --------.> Fe3+ + 3e- E = +0.04V
WHAT IS VALUE OF E* for Fe2+ +2e--------> Fe ?
CO2 + C (charcoal) -------> 2CO
let us consider that initially volume of CO2 is x litre and that of CO is (1-x) litre
so after the above written process net CO in final = 2x+1-x = 1.2 given
on solving x = 0.2 and 1-x = 0.8 now calculate %
MgSO4 --------------> MgSO4 .6H2O
it means 120 gm (mw of compound) gives 228 gm MgSO4 . 6H2O
so 80 gm will give 228*80/120 solve it
here 80 is used for 80% of 100 gm.
Fe+++ + e- -----> Fe++ E= +0.77 V
Fe -----> Fe+++ + 3e- E = +0.04 V
on adding we get
Fe -----> Fe++ + 2e-
so E for the new reaction = [1F(0.77) + 3F(0.04)]/2F = 0.89/2 = 0.445