Reversible Esterification and the Silver Mirror Test
ChemistryOrganic ChemistryAges 16–17Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Organic Chemistry
Esterification mode: a carboxylic acid and an alcohol meet in a test tube with concentrated H₂SO₄ as catalyst; ester and water molecules form until the reaction settles at equilibrium, and changing the alcohol : acid mole ratio recalculates the yield from the equilibrium constant K = 4 with a live yield bar. Silver mirror mode: gently heat a carbonyl compound with Tollens' reagent – an aldehyde deposits a bright silver layer on the tube wall while a ketone does not – along with the equation and the mass of Ag produced.
Lesson: Esterification of carboxylic acids; the silver mirror reaction of aldehydes with Tollens' reagent
What it shows
Two reactions of carbonyl compounds are compared here. Esterification of acetic acid with ethanol or methanol is reversible: with K = 4, equal amounts of acid and alcohol convert only about two thirds of the acid, and extra alcohol raises the yield. In the silver mirror test, Tollens' reagent, [Ag(NH₃)₂]⁺, oxidises an aldehyde while Ag⁺ is reduced to metallic silver; ketones such as acetone have no H on the carbonyl carbon and give no mirror. Formaldehyde gives twice as much silver per mole as acetaldehyde because it is oxidised all the way to carbonate.
How to use
Set Reaction to esterification, choose the Alcohol, change the Moles of alcohol per mole of acid and toggle the Concentrated H₂SO₄ catalyst, then press Run and watch the yield bar settle at equilibrium. Switch Reaction to the silver mirror test, pick a Carbonyl compound and press Run to warm it with Tollens' reagent; compare whether a mirror forms and the mass of Ag produced from 1 mol.
Parameters you can change
- Reaction Esterification (acid + alcohol), Silver mirror test (Tollens)
- Alcohol (esterification) Ethanol C₂H₅OH, Methanol CH₃OH
- Moles of alcohol per mole of acid 0.5–4 mol
- Concentrated H₂SO₄ catalyst
- Carbonyl compound (silver mirror test) Acetaldehyde CH₃CHO, Formaldehyde HCHO, Acetone CH₃COCH₃
Questions to explore
- Why does esterification never reach 100% yield, and how does using 3 mol of alcohol per mole of acid change it?
- Can Tollens' reagent distinguish acetaldehyde from acetone, and what would you observe in each tube?
- Why does 1 mol of formaldehyde produce 4 mol of Ag, while 1 mol of acetaldehyde produces only 2 mol?
