Chemical analysis chapter 22

• sodium flame color (Na+)


  yellow
• Potassium flame color (K+)


  Lilac
• calcium flame color (Ca2+)

  orange-brown
• barium flame color (Ba2+)


  light green
• copper flame color (Cu2+)


  blue
• Aluminium precipitate color


  White precipitate, this redissolves when NaOH(aq) is added to give a clear, colorless solutions
• ammonium NH4 precipitate color when NaOH added

  No precipitate but produces ammonia on warming

  (Halaahad ammonia yalgarna. Tundasgui)
• calcium precipitate when NaOh is added

  White precipitate
• Chromium precipitate when NaOH is added

  green precipitate
• Copper precipitate color when NaOH is added

  light blue precipitate
• Iron precipitate when NaOH is added

  Green precipitate
• Zinc precipitate when NaOH is added

  White precipitate
• Al precipitate when NH3 is added

  White ppt
• NH3 ppt color when NH3 is added


  no change of course
• calcium ppt color when NH3 is added

  no ppt or slight white ppt
• Chromium ppt color when NH3 is added

  Green ppt
• copper ppt color when NH3 is added

  light blue ppt
• Iron ppt color when NH3 is added

  green ppt
• Zinc ppt when NH3 is added

  white ppt
• how to test Carbonate ions

  *CO2 gas will release\bubbles

  *limewater changes from clear to milky
• How to test Halide ions

  *A chloride forms a white ppt

  *A bromide forms a cream ppt

  *An Iodide forms a yellow ppt
• How to test Sulfate Ions


  *addition of barium nitrate

  *if carbonate ions are present, white ppt of BaNO3 will form
• how to test Sulfite ions

  *addition of dilute hydrochloric acid
• How to test Nitrate ions

  *adding aqueous sodium hydroxide, aluminium foil and then heating gently.
• Identify hydrogen 


  * place lighted splint at the neck of test tube. If hydrogen i present, there will be a characteristic “squeaky pop” sound due to a small explosion as oxygen and hydrogen react
• identify oxygen


  Place glowing splint into a test tube of the gas. If oxygen is present, the splint will relight. Bc substances burn much more in pure oxygen.

  *yern shudenz asaagaad still gereltej bvl oxygen bn gesen ug. Untarchihwal no oxygen
• Identify carbon dioxide


  the gas is bubbled through limewater.

  If carbon dioxide is present the limewater turns from clear to milky bc the formation of insoluble calcium carbonate
• identify chlorine gas


  Toxic green gas

  *use damp blue litmus paper to test. It will turn red then bleaches
• identify ammonia gas


  colorless, has pungent odour ( ungugui, ghde hurts unertei)

  * to test, use damp red litmus paper. it will turn blue bc ammonia will dissolve in water to form a weak base
• identify sulfur dioxide gas SO2

  colorless, toxic gas with unpleasant odour

  *pass it over a piece of filter dampened with a solution of acidified potassium manganate. purple color of potassium manganate is removed and solution becomes colorless