Question

K₂Cr₂O₇ is preferred to Na₂Cr₂O₇ for use in volumetric analysis as a primary standard because 

a) Na₂Cr₂O₇ is hygroscopic while K₂Cr₂O₇ is not 

b) K₂Cr₂O₇ is hygroscopic while Na₂Cr₂O₇ is not 

c) K₂Cr₂O₇ is pure while Na₂Cr₂O₇ is impure 

d) none of the above

Answer 1

a) Na₂Cr₂O₇ is hygroscopic while K₂Cr₂O₇ is not