Question

Comment on the purpose of , and write mechanisms for, the following oraganic test reactions

1. Lucas Test

2. Tollens' Test

3 Schiff's Test

4. Semicarbazone Test

Answer 1

dus) Lucas Test Prehrase = The lucas test in alcohols is a .. test to differentiate betweeen. umcey, decondary and teretiwey alcohols. It is based on the difference in reactivity of the three classes of alcohals with hydrogen halides via an Snj reaction l'alcohal no visible oon ② 2 alcohal - Solution forms oily doyer in 3-5 minutes. 3 3 alcohal solution forms an oily layer immediately. Machenisum slawe L. Cele alky charide in sol in water.

2. Tollems test Purpose - Tollens test, also known as silver-missor test , is a qualitative laboratory test used to distinguish between an aldehyde and a Ketone. It explaits the fact that aldehydes wvee readily voxidized , whereas Ketons are not. Mechenisum - Step I = squeaus Miluer mitrate is mixed with aquecos Modium hydroxide , AgNO3 + NaOH - Ag OH + NHO₃ 2 AG OH AgO + H2O steh Is Aq. Ammonia is added drop-wise until the fuecipitated silice oxide completely dissolves. A9 20 + 4 NH3 + 730 — 3 Ay (943)* + 20n Tollens Meagent oxidizes an aldehyde into the Corresponding coreboxylic acid. or + 2Agt +20na a + 2Ag + ho mm HC OH

3) Schiffs test Purhone= The Schiff's test is a relatively genveral chemical test face detection of many couganic caldehydes that has also found lose in the staining of biological tissues. Mechenésum MH SO,H Cuery Hindered e Nucleofhile) Adehyde (ketoneed too hindered -does not react) hosun oy sah 13 molecules Sbhift reagent of aldehyde colorless INH So NAS.H NHISOAH ç-on O Hoc-so, Nu Schiff cedduct. Highly Conjugated (Magenter Colou) NUSO2-(-on

4 • Semicambazone Test Pwepode = Semicarbazone derivatives can be made from Aldehydes and Kelanes. They care ceafrielly foumoe vand easily crespitalized. Semicaubazide res velacted with men aldehyde Que ketone to youm the semicarbazone wou shaven below. oclaten e h K R/h aldehyde Ho NH2 Semi cabaziba ride hyovcechlauide bu ketone HIR HN Nn a semicarbazone. ketones and caldehydes both foum Xomicabazone