Page 1 :
IONIC EQUILIBRIUM, , CHEMISTRY, , IONIC EQUILIBRIUM, 1., , A strong electrolyte is defined as a substance which dissociates almost completely into ions in aqueous, solution and hence is a very good conductor of electricity Ex., NaOH, KOH, HCl, H2SO4, NaCl, KNO3 etc., , 2., , A weak electrolyte is defined as a substance which dissociates to a small extent in aqueous solution and, hence conducts electricity also to a small extent e.g. NH4OH, CH3COOH etc., , 3., , Degree of dissociation :- The fraction of the total amount of an electrolyte which dissociates into ions is, called the degree of dissociation (),, i.e., , 4., , =, , Number of moles dissociated, Number of moles taken, , According to Arrhenius concept of acids and bases, an acid is a substance which gives H + ions in the, aqueous solution whereas a base is a substance which gives OH– ions in the aqueous solution., , 5., , According to Bronsted-Lowry concept of acids and bases, an acid is a substance which can give a proton, and a base is a substance which accepts a proton., , 6., , According to Lewis concept of acids and bases, an acid is a substance which can accept a lone pair of, electrons whereas a base is a substance which can donate a lone pair of electrons., Types of Lewis Bases, ••, , ••, , (i) Neutral molecules containing a lone pair of electrons on the central atom like : NH3, R O H , H 2O : etc., ••, , (ii) All negative ions like F–, Cl–, Br–, l–, OH– etc., Types of Lewis Acids, (i) Molecules having central atom with incomplete octet e.g. BF 3, AlCl3 etc., (ii) Simple cations e.g. Ag+ , Cu2+, Fe3+ etc., (iii) Molecules having central atom with empty d-orbitals e.g. SnCl4, SiF4, PF5 etc., (iv) Molecules containing multiple bonds between different atoms e.g. O = C = O., 7., , According to Ostwald's dilution law, for the solution of a weak electrolyte with concentration, C, mol L–1 and  as the degree of dissociation,, , Ka =, , Cα 2,  Cα 2 or, 1– α, ,  = Ka / C = Ka V, , K a1, Strength of acid HA1, =, Strength of acid HA 2, K a2, , 8., , Relative strength of two weak acids is given by, , 9., , Ionic product of water, Kw = [H+] [OH–] or [H3O+] [OH–]. Its value at 25°C = 10–14, , 10., , pH = –log [H3O+], pOH = –log [OH–], pKa = –log Ka, pKb = – log Kb, IE# 1

Page 2 :
CHEMISTRY, , IONIC EQUILIBRIUM, , 11., , As Kw = [H+] [OH–] = 10–14 therefore pKw = pH + pOH = 14., , 12., , Solubility product of a sparingly soluble salt Ax By is given by, Ksp = [Ay+]x × [B x–]y, Ex. for AgCl, Ksp = [Ag+] [Cl–], for Ca3(PO4)2, Ksp = [Ca2+]3 [PO43–]2 etc., , 13., , If two solutions are mixed in which ions can combine to form a precipitate, concentration of ions in the, solution after mixing are calculated. Then ionic product is calculated using the same expression as for Ksp., If ionic product > solubility product, a precipitate is formed., , 14., , To calculate the solubility of a salt like AgCl in the presence of a strong electrolyte like NaCl, total, [Cl–] is calculated (Cl– ions from AgCl being negligible). Knowing Ksp, [Ag+] can be calculated., , 15., , pH of an acidic buffer is given by Henderson equation viz, , pH = pKa + log, , 16., , [Salt], [Acid], , pH of a basic buffer is given by, , pOH = pKb + log, , [Salt], and then pH = 14 – pOH, [Base], , n, No.of moles of the acid or base added to1litre of buffer, =, ΔpH, Change in pH, , 17., , Buffer capacity =, , 18., , pH of boiling water is 6.5625. It does not mean that boiling water is not neutral. It is due to greater, dissociation of H2O into H+ and OH–., , 19., , pH can be zero in 1 N HCl solution or it can be negative for more concentrated solution like 2N, 3N, 10 N, etc., , 20., , IE# 2, , The buffer system present in blood is H2CO3 + NaHCO3.

Page 3 :
IONIC EQUILIBRIUM, , CHEMISTRY, , IE# 3

Page 4 :
CHEMISTRY, , IE# 4, , IONIC EQUILIBRIUM

Page 5 :
IONIC EQUILIBRIUM, , CHEMISTRY, , IE# 5