Qualitative Inorganic Analysis Quiz

Benedicts reagent is more stable than Fehling's reagent due to the presence of a more stable Cu²⁺-citrate complex compared to the Cu²⁺-tartarate complex in Fehling's reagent.

A solution of iodine is prepared in potassium iodide because iodine is more soluble in KI(aq) than in pure water, due to the formation of the triiodide (I₃^-) ion.

A test used to identify carboxylic acid groups in organic compounds. It involves adding a solution of litmus paper to the compound. A positive test is indicated by a color change from blue to red.

A test used to identify carboxylic acids. A solution of sodium bicarbonate is added to the compound. If bubbles of carbon dioxide gas are produced, it indicates a carboxylic acid is present.

Aromatic compounds containing a hydroxyl (-OH) group directly attached to the benzene ring.

Tests used to identify the presence of a phenolic hydroxyl group (-OH) in an organic compound.

A chemical test used to detect unsaturation in organic compounds. The compound is mixed with a solution of bromine in an organic solvent. A decolorization of the bromine solution indicates the presence of unsaturation (double or triple bonds).

A chemical test used to detect unsaturation in organic compounds. The compound is reacted with an alkaline solution of potassium permanganate. The disappearance of the purple color of potassium permanganate indicates the presence of unsaturation.

A test used to distinguish between aldehydes and ketones. The compound is treated with Tollen's reagent (ammoniacal silver nitrate). Aldehydes react to form a silver mirror on the inside of the test tube, while ketones do not react.

A test used to distinguish between aldehydes and ketones. The compound is treated with Fehling's solution (an alkaline solution of copper sulfate). Aldehydes react with Fehling's solution to produce a red precipitate of copper(I) oxide (Cu2O). Ketones do not react.

A type of organic compound characterized by the presence of a carboxyl group (-COOH). It is a weak acid, typically reacting with carbonates to produce effervescence. Carboxylic acids are also known to react with aldehydes.

A compound containing both a carboxyl group (-COOH) and a hydroxyl group (-OH) attached to a benzene ring. It is known for its medicinal properties and presence in aspirin.

A functional group associated with compounds that react with diazonium salts to form dyes.

A chemical test specific for detecting the presence of carbonyl groups, including aldehydes and ketones.

An organic compound containing a carbonyl group (C=O). This functional group is responsible for its reactivity.

Organic compounds derived from carboxylic acids and alcohols, characterized by a pleasant aroma. Esters are produced through a reaction between carboxylic acids and alcohols.

A chemical test used to detect the presence of both aldehydes and ketones, where the carbonyl group reacts with hydroxylamine to form an oxime.

A compound containing a carbon-oxygen double bond (C=O).

A test used to identify carbohydrates by forming a purple ring when a carbohydrate reacts with α-naphthol in concentrated sulfuric acid. The concentrated sulfuric acid dehydrates the carbohydrate to furfural or its derivatives, which then react with α-naphthol to produce the purple colour.

A reducing sugar is a carbohydrate that can reduce another compound, such as copper(II) ions in Fehling's solution. This reduction is due to the presence of a free aldehyde or ketone group in the sugar molecule.

A non-reducing sugar is a carbohydrate that does not have the ability to reduce other compounds. This is because the aldehyde or ketone group is not free and is involved in a glycosidic linkage.

The red precipitate formed in Fehling's test for carbohydrates is mainly cuprous oxide (Cu2O).

This test detects sesame oil in Vanaspati ghee, distinguishing between Vanaspati ghee and Desi ghee.

Proteins are large polymers made up of smaller monomeric units called amino acids. These amino acids are linked together by peptide bonds.

Amino acids are organic molecules that contain both an amino group (-NH2) and a carboxyl group(-COOH).

Oxalic acid is heated in permanganate titrations to speed up the reaction by liberating Mn²⁺ ions for autocatalysis, and to expel any carbon dioxide evolved.

The linkage -CO-NH- which links one amino acid with another is called a peptide linkage. This linkage is responsible for the formation of polypeptide chains, which are the building blocks of proteins.

The temperature is checked by touching the conical flask. If it is too hot to touch, the solution is around 60-70°C.

Mohr's salt (ferrous ammonium sulfate) shouldn't be heated before titration with KMnO₄ because the reaction with KMnO₄ is already vigorous in cold conditions.

The formula for Mohr's salt is FeSO₄(NH₄)₂SO₄·6H₂O.

Dilute sulfuric acid (H₂SO₄) is the preferred acid for KMnO₄ titrations because it doesn't react with either the permanganate or the reducing agent.

Hydrochloric acid (HCl) cannot be used in place of sulfuric acid because it reacts with KMnO₄ to liberate chlorine gas, which is a side reaction and would interfere with the titration.

A concordant set of readings refers to multiple readings for the same titration that are very close to each other, typically within 0.05 mL, indicating accurate and consistent measurements.

Amides are organic compounds derived from carboxylic acids by replacing the hydroxyl group (-OH) with an amine or ammonia group (-NH2, -NHR, or -NR2).

Nitric acid (HNO₃) cannot be used in KMnO₄ titrations because it's itself an oxidising agent, which would react with the reducing agent and interfere with the titration results.

Primary amines are organic compounds containing an amino group (-NH2) directly attached to a carbon atom that is only bonded to one other carbon atom.

The carbylamine test is a chemical test used to detect the presence of primary amines. It involves reacting the amine with chloroform and a strong base (like KOH) to produce an isocyanide (carbylamine) which has a foul odor.

A functional group is a specific group of atoms within a molecule that is responsible for its characteristic chemical properties and reactions.

Unsaturation in organic chemistry refers to the presence of double or triple bonds between carbon atoms.

The rotten egg smell is often associated with hydrogen sulfide (H2S) gas.

Sodium carbonate (Na2CO3) is a white, odorless crystalline compound. It is used in various industries, including glassmaking, detergents, and paper production. It is also known as washing soda.

Sodium bromide (NaBr) is a white crystalline solid that is soluble in water. It is used as a fire retardant and in photography.