Qualitative Chemical Analysis Review

A comprehensive set of practice flashcards detailing qualitative chemical tests, their expected negative and positive results, and the corresponding structural inferences based on the provided lecture materials.

What is the negative result for the Solubility in Water test?

compound did not dissolve

What is the positive result for the Solubility in Water test?

compound dissolved

In the Solubility in Water test, what is inferred from a positive result?

H-bonding group present for every five carbons ($1:5$ rule) or ionic group present

What is the negative result for the Solubility in DCM test?

compound did not dissolve

What is the positive result for the Solubility in DCM test?

compound dissolved

In the Solubility in DCM test, what is inferred from a positive result?

$1:5$ rule not satisfied or significant VDW moiety present

What is the negative result for the Solubility in $NaOH$ test?

compound did not dissolve

What is the positive result for the Solubility in $NaOH$ test?

compound dissolved

In the Solubility in $NaOH$ test, what is inferred from a positive result?

phenol or carboxylic acid present

What is the negative result for the Solubility in $NaHCO_3$ test?

compound did not dissolve

What is the positive result for the Solubility in $NaHCO_3$ test?

compound dissolved

In the Solubility in $NaHCO_3$ test, what is inferred from a positive result?

carboxylic acid present

What is the negative result for the Solubility in $HCl$ test?

compound did not dissolve

What is the positive result for the Solubility in $HCl$ test?

compound dissolved

In the Solubility in $HCl$ test, what is inferred from a positive result?

amine present

What is the negative result for the Solubility in $H_2SO_4$ test?

compound did not dissolve

What is the positive result for the Solubility in $H_2SO_4$ test?

compound dissolved

In the Solubility in $H_2SO_4$ test, what is inferred from a positive result?

alkene, alkyne, or oxygen-containing functional group present

What is the negative result for the $Br_2$ in light test?

yellow solution

What is the positive result for the $Br_2$ in light test?

clear solution (decolorized)

In the $Br_2$ in light test, what is inferred from a positive result?

alkane present

What is the negative result for the $Br_2$ in dark test?

yellow solution

What is the positive result for the $Br_2$ in dark test?

clear solution (decolorized)

In the $Br_2$ in dark test, what is inferred from a positive result?

alkene or alkyne present

What is the negative result for the Cold, neutral $KMnO_4$ (Baeyer's Test)?

purple solution

What is the positive result for the Cold, neutral $KMnO_4$ (Baeyer's Test)?

decolorized with brown precipitate

In the Cold, neutral $KMnO_4$ (Baeyer's Test), what is inferred from a positive result?

alkene, alkyne, $1^\circ$ or $2^\circ$ alcohol, phenol, or aldehyde present

What is the negative result for the Hot, acidic $KMnO_4$ test?

purple solution

What is the positive result for the Hot, acidic $KMnO_4$ test?

decolorized

In the Hot, acidic $KMnO_4$ test, what is inferred from a positive result?

alkene, alkyne, $1^\circ$ and $2^\circ$ alcohol, phenol, aldehyde, or alkyl benzene present

What is the negative result for the Tollen's Test?

clear solution

In the Tollen's Test, what positive result specifically indicates a terminal alkyne?

white precipitate

What is the inference when a white precipitate is formed in the Tollen's Test?

terminal alkyne present

In the Tollen's Test, what positive result specifically indicates an aldehyde?

silver mirror

What is the inference when a silver mirror is formed in the Tollen's Test?

aldehyde present

What is the negative result for Lucas' Test?

clear solution

In Lucas' Test, what is the positive result for a $3^\circ$ alcohol?

turbid solution (if immediate)

What does immediate turbidity in Lucas' Test indicate?

$3^\circ$ alcohol present

In Lucas' Test, what is the positive result observed for a $2^\circ$ alcohol?

turbid solution (if after heating)

What does turbidity after heating in Lucas' Test indicate?

$2^\circ$ alcohol present

What is the negative result for the $FeCl_3$ Test?

yellow solution

What is the positive result for the $FeCl_3$ Test?

purple solution

What is inferred from a positive result in the $FeCl_3$ Test?

phenol present

What is the negative result for the Iodoform Test?

faintly yellow solution

What is the positive result for the Iodoform Test?

yellow precipitate

What is inferred from a positive Iodoform Test?

2-akanol or methyl ketone present

What is the negative result for the 2,4-DNPH Test?

yellow solution

What is the positive result for the 2,4-DNPH Test?

yellow-orange precipitate

What is inferred from a positive 2,4-DNPH Test?

aldehyde or ketone present

What is the negative result for the Molisch Test?

turbid solution

What is the positive result for the Molisch Test?

purple ring

What is inferred from a positive Molisch Test?

sugar present

What is the negative result for the Benedict's Test?

blue solution

What is the positive result for the Benedict's Test?

brick-red precipitate

What is inferred from a positive result in Benedict's Test?

aliphatic aldehyde or reducing sugar present

What is the negative result for the Ninhydrin Test?

yellow solution

What is the positive result for the Ninhydrin Test?

purple solution

What is inferred from a positive Ninhydrin Test?

free amino acid present

What is the negative result for the Biuret Test?

blue solution

What is the positive result for the Biuret Test?

purple solution

What is inferred from a positive Biuret Test?

polypeptide or protein present

What is the negative result for the Lead acetate Test?

clear solution

What is the positive result for the Lead acetate Test?

black precipitate

What is inferred from a positive Lead acetate Test?

cysteine or cys-containing polypeptide present

In the Litmus Paper Test, what result is obtained when a neutral compound is present?

red litmus paper stays red, blue stays blue

What is the inference of the result "red litmus paper turns blue" in the Litmus Paper test?

basic compound (amine or carboxylate) present

In the Litmus Paper Test, what is specifically inferred if blue litmus paper turns red?

acidic compound (phenolic or carboxylic acid) present

What inference is made when red litmus paper stays red and blue stays blue?

neutral compound present

What is the positive result observed when a basic compound (amine or carboxylate) is tested with litmus paper?

red litmus paper turns blue