Chemistry help needed- read deatails for more information!!!?

Question

im revising for a chemistry test, and it says I need to "Be able to work out which metal is present in solution from the results of a reaction with sodium hydroxidesolution." I hope some one can help! THANKS!

Answer 1

from a solution of metal ions the introduction of hydroxide would cause a precipitaion of hydroxide complex ions of different colours. if the color is not unique a second test adding ammonia is required to deduce the metal ion in solution.

>>green ppt/brown ppt = iron present
>>light blue ppt dissolves in ammonia to form dark blue soln= copper
>>dark green solution that turns purple after ammonia is added=chromium present
>>white ppt, does not dissolve in excess ammonia=aluminium
>>white ppt, dissolves in excess ammonia=zinc

Answer 2

Sodium hydroxide does not attack iron or copper, but many other metals such as aluminium, zinc and titanium are attacked rapidly. In 1986 an aluminium road tanker in the UK was mistakenly used to transport 25% sodium hydroxide solution, causing pressurisation of the contents and damage to the tanker. For this same reason aluminium pans should never be cleaned with lye.

2Al(s) + 6NaOH(aq) → 3H2(g) + 2Na3AlO3(aq)

Many non-metals also react with sodium hydroxide, giving salts. For example phosphorus forms sodium hypophosphite, while silicon gives sodium silicate.

Unlike NaOH, the hydroxides of most metals are insoluble, and therefore sodium hydroxide can be used to precipitate metal hydroxides. One such hydroxide is aluminium hydroxide, used as a gelatinous floc to filter out particulate matter in water treatment. Aluminium hydroxide is prepared at the treatment plant from aluminium sulfate by reaction with NaOH:

Answer 3

Look in your notes, and see which metals from the list would form a solid precipitate when reacted with hydroxide ion -- metals such as barium, beryllium, cadmium, calcium, cobalt, europium, gallium, iron, lead, magnesium, nickel, praseodymium, scandium, thallium, tin, yttrium, and zinc.