Arnold K H Tan's answer to LockB's Secondary 4 A Maths Singapore question.
For Q26 I feel that Ca2+ would be better, since it gives a white precipitate which fails to dissolve in excess NaOH.
In other words, because Ca2+ is going to give a white precipitate either way, it could not have been present in the solution.
Zinc, lead and ammonium might be present because they lead to colourless solutions when excess sodium hydroxide is added to any of them.
In other words, because Ca2+ is going to give a white precipitate either way, it could not have been present in the solution.
Zinc, lead and ammonium might be present because they lead to colourless solutions when excess sodium hydroxide is added to any of them.
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