We have a mixture consistingof 90 mole% 'A' (45 mol/lit) and 10 mole%impurity 'B'(5 mol/lit). To be satisfactory quality the ratio of 'A' to 'B' in the mixture must be 100 to 1or higher. 'D' reacts with both 'A' and 'B' as follows;A + D?R-rA= 21 CACDB + D?S-rB= 147 CBCDAssuming that the reaction go to completion, how much 'D' need be added to a batch of mixture to bring about the desired quality