Physiological pH is between 7.37 and 7.43
Lysine is a basic amino acid, which means
it has two NH2 groups and one COOH group.
Lysine pKas are: 2.16, 9.06 and 10.05
At low pH (lower than the first pKa, in
this case: lower than 2.16) the three groups are protoned. As you increase pH,
the first group to lose its proton is the acid group, then the alpha-amino
group and then the R-amino group. You will have everything non protoned at a
high pH (higher than the highest pKa, in this case: 10.05).
Physiological pH is higher than the lowest
pKa and lower than the middle pKa, so it’s the second case: the acid is
not protoned, the R-amino is protoned and the alpha amino is protoned.
Protoned aminos are cations: NH3+.
Solubility product constants are values to describe the saturation of ionic compounds with low solubility. A saturated solution is when there is a dynamic equilibrium between the solute dissolved, the dissociated ions, the undissolved and the compound. It is calculated from the product of the ion concentration in the solution. For barium chromate, the dissociation would be as follows:
BaCrO4 = Ba^2+ + (CrO4)^2-
So, the expression for the solubility product would be:
Ksp = [Ba^2+] [(CrO4)^2-]
we let x = [BaCrO4] = [Ba2+] = [(CrO4)2-] = 2.81x10^-3 g/L ( 1 mol / 253.35 g ) = 1.11x10^-5
Ksp = x(x)
Ksp= x^2
Ksp = (1.11x10^-5)^2
Ksp = 1.23x10^-10
The Ksp of Barium chromate at that same temperature for the solubility would be 1.23x10^-10.
The addition of sodium chloride to pure water causes the conductivity to INCREASE. The more NaCl present in the water, the higher the conductivity is because NaCl is an electrolyte. Once dissolved in water, it becomes Na and Cl which are corpuscles that conduct electricity.
