Use the interactive explorer below to revise common organic chemistry reagents by transformation, reaction conditions, and exam-focused clues.
First identify the functional group in the starting material. Then ask what the reagent is designed to change: oxidation level, reduction level, leaving group, carbon skeleton, or a diagnostic test. Conditions matter because the same reagent family can give different products under controlled or vigorous conditions.
This is a revision guide for common laboratory and examination reactions. Always follow an approved laboratory protocol and the relevant safety data sheet when handling chemicals.
Chemistry Reagent Explorer is a fundamental concept in organic chemistry. Understanding the mechanisms, reaction conditions, and stereo-chemical outcomes is crucial for mastering organic chemistry. Our curated resources provide step-by-step visualizations to help you excel.
Transformation
Exam tip / mistake to avoid
Mistake to avoid: PCC normally stops a primary alcohol at the aldehyde. Do not confuse it with strong aqueous dichromate, which can continue oxidation to the acid.
Transformation
Exam tip / mistake to avoid
The purple colour disappears with oxidisable unsaturation. Do not assume every KMnO₄ condition gives the same product.
Transformation
Exam tip / mistake to avoid
Orange dichromate turns green. For a primary alcohol, remember that reflux favours complete oxidation to the carboxylic acid.
Transformation
Exam tip / mistake to avoid
Mistake to avoid: LiAlH₄ is moisture-sensitive. Add water or acid only during the work-up, never during the hydride step.
Transformation
Exam tip / mistake to avoid
NaBH₄ is milder than LiAlH₄. In standard conditions it usually reduces aldehydes and ketones without reducing esters or carboxylic acids.
Transformation
Exam tip / mistake to avoid
Hydrogenation adds H₂ across a π bond. Do not forget that catalyst, pressure, and selectivity affect the product.
Transformation
Exam tip / mistake to avoid
Mistake to avoid: Tollens’ reagent is a test for aldehydes, not a general test for every carbonyl compound. Most ketones give no silver mirror.
Transformation
bromine colour is discharged
Exam tip / mistake to avoid
The orange-brown colour disappears with an alkene. Do not call this an oxidation test: it is electrophilic addition across C=C.
Transformation
Exam tip / mistake to avoid
SOCl₂ replaces –OH with Cl. Remember that SO₂ and HCl are by-products, so the reaction is often driven forward as gases escape.
Transformation
Exam tip / mistake to avoid
For a chiral alcohol reacting through an SN2 pathway, expect inversion of configuration.
Transformation
Exam tip / mistake to avoid
Mistake to avoid: water destroys the Grignard reagent. Keep the carbon–magnesium step dry and add acid only during work-up.
Transformation
Exam tip / mistake to avoid
Alcoholic KOH favours elimination, while aqueous KOH more commonly favours substitution.
SELF TEST
Which reagent most commonly oxidises a primary alcohol to an aldehyde without normally continuing to the acid?
LEARNING SUPPORT
Conditions can change the strength and selectivity of a reagent. For example, PCC commonly stops a primary alcohol at an aldehyde, while strong aqueous dichromate can oxidise it further to a carboxylic acid.
Sodium borohydride (NaBH4) is a mild hydride reducing agent commonly used to convert aldehydes and ketones into primary and secondary alcohols, respectively.
A Grignard reagent behaves as a strong base as well as a nucleophile. Water, alcohols, and other acidic hydrogen sources protonate it and destroy the carbon nucleophile.