The additional H present on ammonia (NH₃) requires the generation of the a positive charge on the molecule. This also must be created to balance the negative charge created on the associated anion product.

Amines act as bases due to the lone pair on the nitrogen. Amine basicity can be increased or decreased by functional groups attached to the nitrogen. Electron-withdrawing groups decrease the basicity of an amine by lessening the effect of the lone pair, while electron-donating groups increase basicity by amplifying the lone pair effect. As a result, a secondary amine with an electron-donating functional groups will be the most basic amine.

A secondary amine is an amine (nitrogen atom) that is attached to two carbon-containing groups (alkyl groups or aryl groups). The nitrogen in ephedrine is attached to two alkyl groups, making it a secondary amine.

Primary amines are generally written as . Secondary amines are generally written as . A tertiary amine will be bound to three different R-groups. Quaternary amines require a positive charge on the nitrogen atom to accommodate a fourth R-group.

Nitro groups and amide groups both contain oxygen components, and cannot be found in the compound described. We also know that the benzene ring only has a single constituent, meaning that it cannot be a methylamine. The compound must be benzylamine, a benzene ring with a -CH₂NH₂ substituent.

Enol functional groups contain a hydroxyl group bonded to a carbon involved in a double bond with another carbon (vinyl carbon). An enol will usually undergo tautomerization to become a more stable keto.

Ephedrine contains an arene (the aromatic benzene ring), an alcohol (the -OH group), an amine (the nitrogen-based group), and an N-methyl group (-CH₃ attached to nitrogen). It does not contain a ketone (C=O), or any other carboxyl groups.

When dealing with carbonyl compounds, remember that a carboxylic acid and all of its derivatives will undergo nucleophilic substitution. Aldehydes and ketones will undergo nucleophilic addition. Propanal is a three-carbon aldehyde, and will thus undergo nucleophilic addition.

Acetic acid is a carboxylic acid, methyl ethanoate is an ether, and ethanamide is an amide; each of these would undergo nucleophilic substitution.

Esters have the general molecular formula of , where  and  are carbon groups. The rightmost region of compound A shows an ester.

Ketones have the formula of , with a carbon-oxygen double bond. Ethers have the formula of , with an oxygen linked by single bonds within a carbon chain. An ester resembles adjacent ketone and ether groups. Carboxylic acids have the formula , resembling an ester with a hydrogen in place of a second carbon chain. Finally, the nitrile group has a formula of , with a triple bond between nitrogen and carbon.

Compound A also contains an aromatic function group (the benzene ring) and a nitro group, , on the far left side.

Carbonic acid is a weak organic acid, not nearly as strong as most inorganic acids. It is still, however, an acid, and has a pK_a below 7, but nowhere near as low as 1.4 * 10^-14.

Carbonate is a conjugate base, and thus has an alkaline pK_a around 10.3.

Bicarbonate is the product of deprotonation of carbonic acid. Anything that stabilizes this product will encourage the deprotonation reaction, and resonance is a key stabilizing factor for bicarbonate. Stability of the conjugate base is a major contributing factor to the strength of an acid and its ability to deprotonate.