CIE CHEMISRTY PRACTICALS DOUT

[joel]

In some chemistry practical exam papers, in the inorganic salt analysis section they give a salt which is not in the Notes.
They do not ask us to name the salt but ask us, What the nature of the salt is? What exactly are we supposed to write and how can the nature of any salt be found on testing?

[joel]

In the May/June 2007 (Variant 2) Question Paper FB 8  is Cobalt(II)Sulfate. Cobalt is not given in the notes on qualitative analysis.
In Question 3 (d) last part is States " What conclusion of the nature about the third cation can be drawn from your observations in (C)

In the (C) part they ask you to give your observations of the solution on addition of Sodium Hydroxide and Ammonia.
These are the results of FB8

With Sodium Hydroxide: Blue ppt., Insoluble in excess.
With Ammonia: Blue ppt., Insoluble in excess.

The answer for part (d) according to the mark scheme, "Recognises transition metal cation from various colour
changes of precipitates"
 

[joel]

So should we now the colour changes of all Transition Elements ?

[sahrhp]

If you have actually performed this practical you would know that wat ever you do with the solution containing the cobalt ion the solution which results is colourful. the colours would be different but every solution with cobalt would be coloured. so waht the examiner wants here is that you write that the solution contains a transition ion and that is it. hey donot expect you to name the ion. you should just know it is some transition metal ion in there.