Question

If the precipitate formed is soft, loose and slimy, these are __________ and if the precipitate is hard and adhering on the inner wall, it is called _____________

(a) Sludges, scale

(b) Scale, sludges

(c) Sludges, rodent

(d) Scale, rodent

The question was asked in homework.

The question is from Boiler Feed Water topic in section Water and its Treatment of Engineering Chemistry II

Answer 1

The correct choice is (a) Sludges, scale

The best I can explain: If the precipitate formed is soft, loose and slimy, these are sludges and if the precipitate is hard and adhering on the inner wall, it is called scale. A rodent is a small furry mammal whose teeth never stop growing.