Chem QA

• Jasmine ngjiamin

  6 Aug 11, 18:25

  Pale green solution A---------- (excess aq NH3)----------> Green ppt------(expose to air warming)------------> Red brown ppt C

  What is A and C?

  Then,

  Red Brown ppt C------(solution PH1)-------> Yellow/brown solution B----(bubble SO2)----->A

  What is B?

• UltimaOnline

  6 Aug 11, 20:06

  Originally posted by Jasmine ngjiamin:

  Pale green solution A---------- (excess aq NH3)----------> Green ppt------(expose to air warming)------------> Red brown ppt C

  What is A and C?

  Then,

  Red Brown ppt C------(solution PH1)-------> Yellow/brown solution B----(bubble SO2)----->A

  What is B?

  
  A is Fe2+ (aq)

  C is Fe(OH)3 (s)

  B is any soluble Fe3+ salt, eg. Fe2(SO4)3(aq) or Fe(NO3)3(aq) or FeCl3(aq).

   

• Jasmine ngjiamin

  6 Aug 11, 21:58

  OK thks alot!

• UltimaOnline

  7 Aug 11, 00:23

  Originally posted by Jasmine ngjiamin:

  OK thks alot!

  
  No problem, Jasmine.
  
  Remember to plan ahead beyond 'O' levels. Eg, if you want to do engineering in the Uni, be sure you take H2 Physics and H2 Maths in JC. If you want to do Life Sciences in the Uni, be sure you take H2 Chemistry and H2 Biology in JC. And so on.

  See the NUS list of prerequisite subjects :
  click on 'A' level and Mature applicants (with H1/H2 results)
  http://www.nus.edu.sg/oam/apply/local/prerequisites/BYA-prerequisites.html