Codeine (C18H21NO3) is a narcotic pain reliever that forms a salt with HCl. What is the pH of 0.064 M codeine hydrochloride (pKb of codeine is 5.80)?
Thank you.
Let's call codeine hydrochloride CHCl which makes the cation CH^+ and the anion Cl^-
.........CH^+ + H2O ==> H3O^+ + C
I......0.064.............0......0
C........-x..............x......x
E.......0.064-x
Convert pKb to Kb
Kb for the base = (Kw/Ka for the hydrochloride) = (x)(x)/(0.064-x)
Solve for x. Post your work if you get stuck.
To find the pH of the 0.064 M codeine hydrochloride solution, we need to first determine the concentration of hydrochloride ion (HCl) in the solution. Since codeine hydrochloride is a salt, it dissociates completely in water.
The balanced chemical equation for the dissociation of codeine hydrochloride in water can be written as:
C18H21NO3.HCl (s) → C18H21NO3+ (aq) + Cl- (aq)
Since 1 mole of codeine hydrochloride produces 1 mole of chloride ions, the concentration of chloride ions will also be 0.064 M.
Next, we need to calculate the pOH of the solution using the concentration of chloride ions. The relationship between pOH and concentration is given by the equation:
pOH = -log10[Cl-]
pOH = -log10(0.064)
pOH = 1.19
Since pH + pOH = 14, we can calculate the pH of the solution:
pH = 14 - pOH
pH = 14 - 1.19
pH ≈ 12.81
Therefore, the pH of the 0.064 M codeine hydrochloride solution is approximately 12.81.
To find the pH of a solution of codeine hydrochloride, we need to determine the concentration of H+ ions in the solution.
Codeine hydrochloride (C18H21NO3) reacts with HCl to form a salt, which dissociates into its ions in water:
C18H21NO3.HCl → C18H21NO3- + H+
Given that the solution has a concentration of 0.064 M codeine hydrochloride, it means that the concentration of H+ ions will also be 0.064 M.
To find the pH, we can use the formula for pH, which is defined as the negative logarithm (base 10) of the concentration of H+ ions in a solution:
pH = -log[H+]
So, we have:
pH = -log(0.064)
Calculating this using a calculator, we find that the pH of the 0.064 M codeine hydrochloride solution is approximately 1.19.