Question

What is the formula of brown ppt?
A.$Fe{(OH)_3}$
B.$Fe{(OH)_2}$
C.$FeC{l_3}$
D.None of these

Answer 1

Hint: The production of a solid in a solution or inside another solid during a chemical reaction or by diffusion in a solid is known as precipitation. The precipitate is the solid created when a reaction happens in a liquid.

Complete answer: $Fe{(OH)_3}$ - The chemical compound iron (III) oxide-hydroxide, also known as ferric oxyhydroxide, is a mixture of iron, oxygen, and hydrogen having the formula FeO. One of the hydrates of the chemical is frequently seen.
$Fe{(OH)_2}$ - Iron (II) hydroxide, often known as ferrous hydroxide, is a chemical substance. When iron (II) salts, such as iron (II) sulphate, are reacted with hydroxide ions, it is formed. Iron (II) hydroxide is a white solid with a greenish tint due to residues of oxygen.
$FeC{l_3}$ - As a flocculant, ferric chloride is used. Flocculants are substances that aid in the clumping of small particles so that they can be removed from water. Even after huge trash is removed with filters, natural surface water may still include microscopic particles that are too small to sink. These merely float in the water, making the water appear hazy. On standing, ferric chloride in an aqueous solution hydrolyzes to ferric hydroxide and hydrochloric acid. The production of ferric hydroxide results in the brown precipitate.
So, we conclude that $FeC{l_3}$ is the formula of brown ppt.
So, the final answer is option(C) i.e. $FeC{l_3}$ .

Note:
When certain cations and anions mix in an aqueous solution, precipitates occur, which are insoluble ionic solid products of the interaction. Precipitate reactions create crystalline solids that might be suspended throughout the liquid or sink to the bottom of the solution.