Final answer:
The pH of a .84M solution of lidocaine at 25°C is 13.92.
Step-by-step explanation:
To calculate the pH of a .84M solution of lidocaine at 25°C, we need to consider that lidocaine is a weak base with a pKb of 7.94. To find the pH, we can first calculate the pOH by taking the negative logarithm of the hydroxide ion concentration, which is equal to the concentration of lidocaine in this case.
pOH = -log(0.84) = 0.08.
Next, we can find the pH by subtracting the pOH from 14.
pH = 14 - 0.08 = 13.92.