Question

why does on passing H2S , CoS gives precipitate in alkaline medium?​

Answer 1

NAZUAK❤

- Due to the low value of their solubility product, they form precipitates on passing H2S gas in acidic medium. - But zinc is a 3rd group cation. - It has comparatively higher solubility product value due to the common ion effect. - Hence, it will not form a precipitate in acidic medium on passing H2S gas.