Question

PreLab - ID of Liquid Unknown 1. A liquid which is soluble in water, 5% aq. NaOH and 5% aq. HCl is suspected of being an amine. What feature of the solubility tests would confirm whether or not it is an amine? Explain. 2. While the effect is generally small enough to he neglected, what variable of laboratory conditions can alter the measured boiling point temperature of the liquid? 3. Match the letter of the functional group to the description of the qualitative test for which it is specific B. carbonyls (general) C. phenols A land 2 alcohols D. aldehydes E.methyl ketones Dissolve sample in 10% aqueous NaOH, add 1/Kl solution until brown color persists and look for appearance of yellow precipitate. Add drop of sample to 2,4-DNP reagent and look for brightly colored (red, yellow, orange, etc, depending on structure) precipitate. Dissolve sample in water or aqueous ethanol, add FeCl reagent and look for dark color, typically blue, or red-purple). Dissolve a drop of sample in I mL of acetone, add CrO/H SO, reagent and look! for appearance of a dark, opaque green-to-blue color. Add a drop of sample to a freshly prepared solution of [Ag(NH3)2]+ and let stand for 4 minutes (warm gently if no reaction). looking for appearance of either a silver mirror on the test tube walls or a black precipitate of finely-divided metallic Ag.

Answer 1

R-Nyt Hel RNH Amine (soluble salt) V NaoH RNA + Nach + H₂O (Reappearance of amire) 21 [ Pressure) Because atmospheric pressure is usually considered content, latm . 3) a) Rad un Naonling R- Conat + chlist Methyl ketone (Yellowppt) Iodo form test [E]Methyl Ketone. NO HN-ko Carbonyl - 24-dne 2,4-DNP hydrazone, 2,4-DNP test → ② carbonyl. Oh fell b e Phenol violetcomplex (ferric phenoxide) Fellz test ② phenols. D OH Crozlut u & alcohol (ketone ) I Chromie auid test: Alcohols ② + R-CHO +(Ag (NH4), it → Root Agt aldehyde Tollen's test: aldehydes 6 Grey meror