Identification of Ions and Instrumental Methods of Analysis

Vocabulary flashcards covering qualitative identification tests for cations and anions, chemical tests for gases, and instrumental analytical methods including flame photometry.

Unique ion test

A test specific to a single substance, required because identification would be impossible if more than one ion gave the identical result.

Flame test

A qualitative testing procedure where a sample is held on a wire in a roaring Bunsen burner flame to observe the characteristic flame colour of metal cations.

Lithium ion ($Li^+$) flame test result

Produces a red flame when placed in a roaring Bunsen burner flame.

Sodium ion ($Na^+$) flame test result

Produces a yellow flame when placed in a roaring Bunsen burner flame.

Potassium ion ($K^+$) flame test result

Produces a lilac flame when placed in a roaring Bunsen burner flame.

Calcium ion ($Ca^{2+}$) flame test result

Produces an orange-red flame when placed in a roaring Bunsen burner flame.

Copper ion ($Cu^{2+}$) flame test result

Produces a blue-green flame when placed in a roaring Bunsen burner flame.

Aluminium ion ($Al^{3+}$) sodium hydroxide test

Forms a white precipitate upon the addition of sodium hydroxide ($NaOH$) solution that dissolves when excess $NaOH$ is added.

Calcium ion ($Ca^{2+}$) sodium hydroxide test

Forms a white precipitate upon the addition of sodium hydroxide solution that does not dissolve in excess $NaOH$.

Copper ion ($Cu^{2+}$) sodium hydroxide test

Forms a blue precipitate upon the addition of sodium hydroxide ($NaOH$) solution.

Iron(II) ion ($Fe^{2+}$) sodium hydroxide test

Forms a green precipitate upon the addition of sodium hydroxide ($NaOH$) solution.

Iron(III) ion ($Fe^{3+}$) sodium hydroxide test

Forms a brown precipitate upon the addition of sodium hydroxide ($NaOH$) solution.

Ammonium ion ($NH_4^+$) test

Produces a pungent-smelling gas (ammonia) when reacted with sodium hydroxide solution, which turns damp red litmus paper blue.

Chemical test for ammonia

Turns damp red litmus paper blue and produces a white smoke of ammonium chloride when held near hydrogen chloride gas from concentrated hydrochloric acid.

Carbonate ion ($CO_3^{2-}$) test

Reacts with dilute acid to produce carbon dioxide gas ($CO_2$), which turns limewater cloudy when bubbled through it.

Sulfate ion ($SO_4^{2-}$) test

Produces a white precipitate upon the addition of dilute hydrochloric acid ($HCl$) followed by barium chloride solution.

Chloride ion ($Cl^-$) test result

Produces a white precipitate after adding dilute nitric acid followed by silver nitrate solution.

Bromide ion ($Br^-$) test result

Produces a cream precipitate after adding dilute nitric acid followed by silver nitrate solution.

Iodide ion ($I^-$) test result

Produces a yellow precipitate after adding dilute nitric acid followed by silver nitrate solution.

Instrumental methods of analysis

Techniques used to detect and identify elements and compounds, such as gas chromatography and mass spectrometry, that improve sensitivity, accuracy, and speed compared to traditional chemical tests.

Flame photometer

An instrumental device that passes light emitted from a sample in a flame through a photometer to produce a line spectrum for identifying metal ions and determining their concentrations.

Line spectrum (flame photometry)

The spectroscopic output generated by a flame photometer that is compared with reference data to identify metal ions and determine their concentration.

Calibration curve (flame photometry)

A standard reference plot used to determine the concentration of metal ions in dilute solution from flame photometer output data.