Question

Can someone PLEASE help me! I have missed a few days of school due to sickness and my teacher is making me make up a lab! She gave me some things to study, but Chemistry is NOT one of my strong suits by any means! I only have 3 questions! I will post them separately to save room. Here is the first.
1. List at least two chemical reactions that result in a yellow, orange, or red precipitate. For these reactions list the possible chemical name of the precipitate. What do these reactions (and the others similar to them) have in common?

Answer 1

2,4-dinitrophenylhydrazine (Brady’s reagent) is an important reagent related to hydrazine. Most aldehydes and ketones very readily with this reagent to give the yellow orange and red precipitates of 2,4-dinitrophenylhydrazones.
Unconjugated aldehydes and ketones give precipitates toward the yellow while conjugated compound tend to be deeper colour of red.
The conversion of aldehydes and ketones into hydrazone is an example of the addition-elimination reaction occurring at the unsaturated carbonyl group.