Question

Give an example of a reaction which produce a black ppt

Answer 1

Answer:

Sometimes when two liquids combine, a solid forms and falls to the bottom of the liquid. This solid is a new substance, called a precipitate, and is evidence that a chemical reaction has occurred. Soap scum, a common example of a precipitate, forms when certain minerals in hard water react with soap molecules.

Answer 2

Explanation:

So the reaction in which balck precipitate formed is

HS + AgCl gives rise to AgS + HCl

AgS is black precipitate