What is the molarity of each ion in a solution of (a) 2.0 M NaCl and (b) 0.40 M K2SO4 Assume complete dissociation.
What is the molarity of each ion in a solution of (a) 2.0 M NaCl and (b) 0.40 M K2SO4 Assume complete dissociation.
(a) According to the dissociation equation,
NaClH2ONa+(aq)+Cl−(aq)1 mol 1 mol 1 mol
the concentration of Na+ is equal to that of NaCl : 1 mol NaCl → 1 mol Na+ and the concentration of Cl− is also equal to that of NaCl Therefore the concentrations of the ions in 2.0 M NaCl are 2.0 M Na+ and 2.0 M Cl−
(b) According to the dissociation equation
K2SO4H2O2K+(aq)+SO42−(aq)1 mol 2 mol 1 mol
the concentration of K+ is twice that of K2SO4 and the concentration of SO42− is equal to that of K2SO4 .Therefore the concentrations of the ions in 0.40 M K2SO4 are 0.80 M K+ and 0.40 M SO42−