Interactive Chemistry Worksheets for Students |
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A precipitation reaction is a reaction in which two solutions are mixed to produce an insoluble solid called a precipitate.
Simplified Solubility Rules :If a compound contains one of the following chemicals it is always soluble
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Physical states
(aq) = aqueous and (s) = solid
Student Instructions
Valency 1 |
Valency 2 |
Sodium Na+, potassium K+, silver Ag+, |
Mercury Hg2+, Copper Cu2+, Lead Pb2+ |
1. Sodium hydroxide + silver nitrate sodium nitrate + silver hydroxide (brown)
NaOH(aq) + AgNO3(aq) NaNO3(aq) + AgOH(s)
2. Sodium hydroxide + copper sulfate sodium sulfate + copper hydroxide (blue)
2NaOH(aq) + CuSO4(aq) Na2SO4(aq) + Cu(OH)2(aq)
3. Potassium iodide + lead nitrate potassium nitrate + lead iodide (yellow)
2KI(aq) + Pb(NO3)2(aq) 2KNO3(aq) + PbI2(s)
4. Potassium iodide + mercury nitrate mercury iodide (orange) + potassium nitrate
2KI(aq) + Hg(NO3)2(aq) HgI2(s) + KNO3(aq)
5. Potassium iodide + silver nitrate potassium nitrate + silver iodide (white/ yellow)
KI(aq) + AgNO3(aq) KNO3(aq) + AgI(s)
6. Sodium chloride + silver nitrate sodium nitrate + silver chloride (white)
NaCl(aq) + AgNO3(aq) NaNO3(aq) + AgCl(s)
7. Mercury nitrate + potassium fluoride mercury fluoride + potassium nitate
Hg(NO3)2(aq) + 2KF(aq) HgF2(aq) + 2KNO3(aq)
8. Copper sulfate + potassium iodide copper(II) iodide + potassium sulfate
CuSO4(aq) + 2KI(aq) CuI2(s) + K2SO4(aq)
Note: The above reaction is more complex. Copper(I) iodide, CuI is formed with iodine, I2(aq)
This equation is technically correct. 2CuSO4(aq) + 4KI(aq) 2CuI(s) + 2K2SO4(aq) + I2(aq) (overall brown/ red)
The iodine ions reduce the copper(II) ions to copper(I).