9 1 qualitative analysis tests for ions

A flame test is used to identify metal ions by the colour of the flame they produce when heated.

True. The Bunsen burner flame should be on a blue flame for flame tests as this is the hottest flame.

The flame colour produced by sodium ions is yellow.

The flame colour produced by copper ions is blue -green.

False. The flame colour produced by potassium ions is lilac.

The flame colour produced by calcium ions is orange-red.

True. The flame colour produced by lithium ions is red.

The nichrome wire is first dipped in hydrochloric acid to avoid contamination.

A cation is a positively charged ion.

The formula of an ammonium ion is NH4+.

The colour of the precipitate formed when sodium hydroxide is added to a solution containing copper(II) ions is blue.

False. Iron(III) ions form a brown precipitate in the presence of sodium hydroxide.

The two positive ions which form a white precipitate are Ca2+ and Al3+.

The test for ammonium ions is:

The colour of the precipitate formed by iron(II) ions in the presence of sodium hydroxide is green.

False. Ca2+ form a white precipitate in the presence of sodium hydroxide.

A test that would distinguish between these two ions are add excess sodium hydroxide solution. The white precipitate formed by aluminium ions will dissolve in excess NaOH, but the calcium one won't

The formula of ammonia is NH3.

The test and result for ammonia gas is that it turns damp red litmus paper blue.

True. Ammonia has a pungent smell.

True. When ammonia is reacted with HCl, ammonium chloride is formed

One observation when ammonia reacts with HCl is white smoke.

An anion is a negatively charged ion.

The test and result for bromide ions is:

The formula of a carbonate ion is CO32-.

The test for carbonate ions is:

The test and result for iodide ions is:

True. Chloride ions give a white precipitate with silver nitrate solution.

False. To test for sulfate ions, acidified barium chloride is used.

The white precipitate formed during a positive test for sulfate ions is barium sulfate.

The state symbol for the precipitate of silver bromide is s.

The formula of the precipitate formed when silver nitrate solution is added to a solution containing iodide ions is AgI.

Methods of instrumental analysis include:

Advantages of instrumental analysis over traditional methods of chemical analysis include:

Flame emission spectroscopy works by exposing the sample to a very hot flame and then measuring the intensity and wavelength of the light emitted.

Ions in unknown samples can be identified using flame emission spectroscopy by comparing the sample spectrum to reference spectra.

Flame emission spectroscopy can be used to determine the concentration of metal ions in a solution by reference to a standard solution of known concentration, as the intensity of the light produced is proportional to the number of ions vaporised.