Chemistry question

1a) Use Zinc sulphate solution to displace copper from the solid. Solution becomes blue.
b) Add aqueous silver nitrate into the solution. White precipitate will form.

2 Add sodium hydroxide into both solution, the one with Calcium will form white precipitate while the one with potassium will not form any precipitate.

2006-10-22 22:14:58 補充：
1b ) Precipitate will be soluble in when dilute NH3(aq) is added on the precipitate.

1a)Flame test
Dip a nichrome/platinum wire into HCl. After that, dip the wire into the sample of blue solid. Put the wire in non-luminous flame and greenish-blue colour will be seen if there is Copper(II) in the compound.

1b)Silver chloride test
Add excess silver nitrate to the solution. White precipitate appears if there is chloride ion in the compound.
The reaction can be represented by the following equation:
Ag+(aq) + Cl-(aq) → AgCl(s)



2. Method 1:
Add H2CO3 into the solutions. White precipitate will form in the solution with Ca2+ due to the following equation:
Ca2+(aq) + CO3-(aq) →CaCO3(s)

Method 2:Flame test
Dip a nichrome/platinum wire into HCl. After that, dip the wire into the sample. Put the wire in non-luminous flame, that with calcium will show brick red flame and that of potassium is purple.