"Calculate valency factor and equivalent wieght of the following" `Na_(2)CO_(3), " " Fe_(2)(SO_(4))_(3), " " FeSO_(4).7H_(2)O`
A. n-factor for Hydroxyl amine is 1
B. equivalent weigth of `Fe_(2)(SO_(4))_(3)` is `M//2`
C. 6 meq of `Fe_(2)(SO_(4))_(3)` is contained in 3 millimoles of ferric sulphate
D. all of these
