I guess is weak alkaline. when the substance is more acidic, there will be less alkalinity
Since medals form cations
nonmedals form anions
21 kg x [(3 x 35.45)/(12.01 + 19.00 + (3 x 35.45))] =
21 kg x (106.35/137.36) = 16.3 kg of chlorine
You just multiply the weight of the material by the fraction of chlorine (by weight). The others are done the same way