1. Qualitative analysis identifies substances by their properties, while quantitative analysis determines amounts. 2. Tests for color, smell, solubility, and pH can help identify substances. Common cation tests use sodium hydroxide or ammonia to cause color changes. 3. Anion tests often involve precipitation and can identify carbonate, chloride, iodide, and sulfate ions. A series of video links provide examples of common cation and anion tests.

1. 1. Introducing Chemical Analysis
• Qualitative analysis is used to identify chemical
species (elements, compounds and ions) present in
an unknown substance.
• Quantitative/Volumetric analysis is used to
determine the amount or concentration of these
chemical species (elements, compounds and ions)
present.

2. 2. Use of Physical Tests to Identify
Substances
• Additional tests are needed to identify a substance:
– Colour
– Smell
– Solubility in water
– pH
Calcium compounds Solid copper(II) Aqueous iron(III) ions are
are white. sulfate is blue. yellow-orange.

3. 3. Identification of Ions
Testing for Cations
• Cations are positively-charged ions.
• Aqueous sodium hydroxide and aqueous
ammonia can be used to identify cations in
salts.
• Cations can be identified:
– From the colour of the precipitate,
and
A precipitate of zinc
– If the precipitate dissolves in excess hydroxide
alkali.
Identifying an ammonium
compound.

4. Test for ammonium ions, NH4+
http://www.youtube.com/watch?v=b28pw1q2qdo&feature=related
Test for calcium ions, Ca2+
http://www.youtube.com/watch?v=AvnLlWVOa44&feature=related
Test for lead(II) ions, Pb2+
http://www.youtube.com/watch?v=CPnG4OKxgEQ&feature=related
Test for zinc ions, Zn2+
http://www.youtube.com/watch?v=JjPNDnoxYN4&feature=related
Test for aluminium ions, Al3+
http://www.youtube.com/watch?v=D3s-_0xUS-k&feature=related
Test for copper(II) ions, Cu2+
http://www.youtube.com/watch?v=KLGRf4AdKQM&feature=related
Test for iron(II) ions, Fe2+
http://www.youtube.com/watch?v=bivr2CzlTF4&feature=related
Test for iron(III) ions, Fe3+
http://www.youtube.com/watch?v=gj7ju9wRtdY&feature=related

5. Using aqueous sodium hydroxide to distinguish:
sodium, potassium and ammonium ions
http://www.youtube.com/watch?v=kAnEzELqfjQ&feature=youtu.be
calcium, aluminium, lead and zinc ions
http://www.youtube.com/watch?v=cxOjcN_G4zg&feature=youtu.be
iron(II), iron(III) and copper(II) ions
http://www.youtube.com/watch?v=iKQ-uPqx4n4&feature=youtu.be
Using aqueous ammonia to distinguish:
sodium, potassium and calcium ions
http://www.youtube.com/watch?v=G0lYQH4OVqA&feature=youtu.be
aluminium, lead(II) and zinc ions
http://www.youtube.com/watch?v=UjLBaKZZ_2k&feature=youtu.be
iron(II), iron(III) and copper(II) ions
http://www.youtube.com/watch?v=xaRPwuAOqpc&feature=youtu.be

6. 3. Identification of Ions
Testing for Cations

7. 3. Identification of Ions
Testing for Cations
• Cations can be identified with
aqueous sodium hydroxide.

8. 3. Identification of Ions
Testing for Cations
• Cations can be identified with
ammonia solution.

9. 3. Identification of Ions
Testing for Anions
• Anions are negatively-charged ions.
• Tests for carbonate, chloride, iodide and sulfate often involves precipitation
reactions.

10. 3. Identification of Ions
Testing for Anions
Testing for two anions: (a) carbonate and (b)
iodide

11. Test for carbonate ions, CO32−
http://www.youtube.com/watch?v=197iyKaRhtA&feature=related
Test for sulfate ions, SO42−
http://www.youtube.com/watch?v=oEXYjqSUg4g&feature=related
Test for chloride ions, Cl−
http://www.youtube.com/watch?v=vcQXdeL-juM&feature=related
Test for iodide ions, I−
http://www.youtube.com/watch?v=lw5VUL4-O8M&feature=related
Test for nitrate ions, NO3−
http://www.youtube.com/watch?v=NyB5XfbSwSo&feature=channel

12. Test for halides (Cl−, I−) using dilute nitric acid and
aqueous silver nitrate
http://www.youtube.com/watch?v=C2Lh48zAyqk&feature=youtu.be
Test for halides (Cl−, I− ) using dilute nitric acid and
aqueous lead(II) nitrate
http://www.youtube.com/watch?v=xAsHDFfCR14&feature=youtu.be

13. 4. Testing for Gases and Water
Testing for Gases
sulfite +
acid mixture
Testing for sulfur
dioxide gas

14. 4. Testing for Gases and Water
Testing for Water
• Test liquid with a piece of blue anhydrous cobalt(II)
chloride paper.
• Water turns blue anhydrous cobalt(II) chloride paper
pink.
Test for water