Question

The sample is dissolved in hot con. $HCl$ and add few drops of $N{H}_{4}OH$, then acidified with dil. Acetic acid + few drops of potassium ferrocyanide solution. The precipitate is obtained. Guess the color of precipitate.

• A. Red
• B. Blue
• C. White
• D. Chocolate brown

Answer 1

The correct option is D Chocolate brown

Potassium ferrocyanide precipitates brown coloured copper(II) ferrocyanide from Cu²⁺ solutions. The equation can be written as:

$C{u}^{2+}+\left[Fe\right(CN{)}_6{]}^{4-}\to C{u}_2\left[Fe\right(CN{)}_6\left]\right(s\left)\right)$