ChemistryChapter 19: Carbonyl Compounds
Exam Response (carbonyls and Acids)
Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products.
Learning objectives
- Explain exam response (carbonyls and acids) in simple chemical language.
- Connect 1. tests with 2. conversions using equations, observations, or trends where needed.
- Answer a short Federal Board question with the correct terms and a clear reason.
Definition
Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products. Stack tests. No HCN how-to beyond the named product. Unknown carbonyl: Tollens distinguishes aldehyde; iodoform for methyl ketone. Tollens distinguishes aldehyde from ketone; iodoform targets methyl carbonyl or ethanol specifically.
Important terms
- EXAM RESPONSE (CARBONYLS AND ACIDS)
- Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products.
- 1. TESTS
- DNPH both.
- 2. CONVERSIONS
- NaBH4 alcohol.
Relationship
- mirror = aldehyde
- fizz = carboxylic
Overview
Tests, then conversions:
Tests
DNPH both. Tollens/Fehling al only. Iodoform methyl carbonyls. Carbonate acids. PCl5 both acids and alcohols (then fizz to sort). Acid test: CO2 with NaHCO3.
Examples Mirror · Brick red · CHI3 · CO2
Conversions
NaBH4 alcohol. Acid + alcohol ester. 1 alcohol reflux acid. Hydration of ethene to ethanol sits next door. Name: propanal vs propanone locant and suffix.
Examples Ethanal -> ethanol · Ethanoic + ethanol ester · No drug routes
WHAT — EXAM RESPONSE (CARBONYLS AND ACIDS)
Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products. Stack tests. No HCN how-to beyond the named product. Unknown carbonyl: Tollens distinguishes aldehyde; iodoform for methyl ketone. Tollens distinguishes aldehyde from ketone; iodoform targets methyl carbonyl or ethanol specifically.
WHY — Why this topic matters
EXAM RESPONSE (CARBONYLS AND ACIDS) is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.
HOW — How it works
TESTS: DNPH both. Tollens/Fehling al only. Iodoform methyl carbonyls. Carbonate acids. PCl5 both acids and alcohols (then fizz to sort). Acid test: CO2 with NaHCO3. Examples: Mirror; Brick red; CHI3; CO2. CONVERSIONS: NaBH4 alcohol. Acid + alcohol ester. 1 alcohol reflux acid. Hydration of ethene to ethanol sits next door. Name: propanal vs propanone locant and suffix. Examples: Ethanal -> ethanol; Ethanoic + ethanol ester; No drug routes. Worked 4-mark unknown C3H6O: DNPH ppt: carbonyl Tollens no: ketone iodoform yes: propanone not propanal State that ketones cannot be oxidised by mild agents — reason for Fehling negative.
Worked example
- Worked 4-mark unknown C3H6O:
- DNPH ppt: carbonyl
- Tollens no: ketone
- iodoform yes: propanone
- not propanal
- State that ketones cannot be oxidised by mild agents — reason for Fehling negative.
In simple words
Carbonyl exams. No cyanide how-to, no drug synthesis.
Key points
- mirror = aldehyde
- fizz = carboxylic
- stack
- names of reagents
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Exam Response (carbonyls and Acids)
Sticky Notes · Quick Revision
Core Idea
- Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products. Stack tests. No HCN how-to beyond the named product. Unknown carbonyl: Tollens distinguishes aldehyde; iodoform for methyl ketone. Tollens distinguishes aldehyde from ketone; iodoform targets methyl carbonyl or ethanol specifically.
1. TESTS
- DNPH both. Tollens/Fehling al only. Iodoform methyl carbonyls. Carbonate acids. PCl5 both acids and alcohols (then fizz to sort). Acid test: CO2 with NaHCO3.
- Mirror
- Brick red
- CHI3
- CO2
2. CONVERSIONS
- NaBH4 alcohol. Acid + alcohol ester. 1 alcohol reflux acid. Hydration of ethene to ethanol sits next door. Name: propanal vs propanone locant and suffix.
- Ethanal -> ethanol
- Ethanoic + ethanol ester
- No drug routes
Exam Example
- Worked 4-mark unknown C3H6O:
- DNPH ppt: carbonyl
- Tollens no: ketone
- iodoform yes: propanone
- not propanal
- State that ketones cannot be oxidised by mild agents — reason for Fehling negative.
Common Misconceptions
- Do not confuse 1. TESTS with 2. CONVERSIONS; state the difference before giving an example.
- Writing only “mirror = aldehyde” is not enough. Explain what it means in a complete sentence.
FBISE Exam Check
- Explain exam response (carbonyls and acids), compare its two main parts, and include the correct chemical evidence.
- Carbonyl exams. No cyanide how-to, no drug synthesis.
60-second revision
- Typical tasks: al vs ketone tests; DNPH then Tollens; iodoform on propanone; carbonate fizz; esterification; reduction products.
- 1. TESTS: DNPH both.
- 2. CONVERSIONS: NaBH4 alcohol.
- Exam reminder: Worked 4-mark unknown C3H6O: DNPH ppt: carbonyl Tollens no: ketone iodoform yes: propanone not propanal State that ketones cannot be oxidised by mild agents — reason for Fehling negative.
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