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Important Chemical Reactions

Halogenation by Electrophilic Addition Reactions in Alkenes

Single and Double Replacement Reactions and Net Ionic Reactions

How to Draw Lewis Dot Structure

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Single and Double Replacement Reactions and Net Ionic Equations

Single Replacement Reactions :

When one element displaces another element from a compound and takes its place, the reaction is called a Single Replacement reaction. This is based on reactivity series of the elements .

Examples of Single Replacement Reactions

Less reactive metal can not displace more reactive metal from its compounds .

Zn (s)+ CuSO4 (aq) ZnSO4 (aq) + Cu(s)

Color changes from bluish green to colorless.

Zn is more reactive than Cu

ZnSO4 (aq) + Cu(s) No reaction

Cu is more reactive than Zn

Fe (aq)+ CuSO4 (aq) FeSO4(aq) +Cu(s)

Color of the solution changes from blue to light green .

Mg(s) + ZnCl2(aq) MgCl2(aq)+Zn (s)

2KI(aq) + Cl 2 (g)2KCl(aq) + I 2 (s)

Zn (s)+ MgCl2(aq) no reaction

2K(s)+2H2O 2 KOH(aq) + H2(g)

2 Na(s) +2H2O(l) Ca(OH)2 (aq)+ H2(g)

Mg (s)+H2O (aq)Mg(OH)2 (aq)+H2 (g)

Fe(s)+ 4H2O(l) Fe3O4(aq)+4H2(aq)

2K(s) + 2HCl(aq) 2 KCl (aq)+H2 (g)

Violent reaction with Cold dilute acid

Zn(s)+2HCl(aq) ZnCl2(aq)+H2(aq)

Reacts Vigorously with Cold dilute acid

Fe(aq)+2HCl(aq) FeCl2+H2

Reacts Slowly quietly with Cold dilute acid

Pb (aq)+ HCl(aq) PbCl 2 (aq)+H2 (aq)

Reacts with Hot Conc acid

Double Displacement Reaction :

A reaction in which the constituent of two compounds mutually exchange their ionic radicals to form two different compounds is called a double decomposition reaction.

Examples of Double Replacement Reactions

Na2SO4 (aq)+ CaCl2 (aq) CaSO4 (aq)+ 2 NaCl (aq)

Precipitation reaction : In aqueous medium compounds react to form an insoluble residue as one of the products.

NaCl (aq) + AgNO 3 (aq) AgCl (s) + NaNO3

Pb (NO3)2 (aq) + Na2SO4 (aq) PbSO4 (S) + 2NaNO3 (aq)

FeCl2 (aq) + 2NaOH (aq) Fe (OH)2 (S)+ 2NaCl (aq)

Solubility Chart

Solubility of Common Compounds in Water


Negative Ions (Anions) Positive Ions (Cations)
essentially all alkali ions
soluble*Alkali ions = Li+, Na+, K+, Rb+, Cs+, Fr+
essentially all hydrogen ion, H+
essentially all ammonium ion, NH4+
nitrate, NO3- essentially all
acetate, CH3COO- essentially all
chloride, Cl-
bromide, Br-
iodide, I-

Ag+, Pb2+, Hg22+, Cu1+ low solubility

all others are soluble

sulfate, SO42- Ca2+, Sr2+, Ba2+, Pb2+, Ra2+, Ag+, Hg2+low solubility

all others soluble

sulfide, S2-

alkali ions*,
H+, NH4+, Be2+, Mg2+, Ca2+, Sr2+, Ba2+, Ra2+

all others
low solubility

hydroxide, OH-

alkali ions*, H+, NH4+, Sr2+, Ba2+, Ra2+ soluble

all others low solubility

phosphate, PO43- ,
carbonate, CO32-,
sulfite, SO32-

alkali ions*, H+, NH4+ low solubility

all others

FeCl 2 (aq) + 2NaOH (aq) Fe(OH) 2 (aq) + 2NaCl (aq)

Pb(NO3)2 (aq) + Na2SO4 (aq) PbSO4 (s) + 2 NaNO3 (aq)