Equilibrium of Acids and Bases with Conjugate Pairs

1) The pKas and structures of several substances for several organic acids are shown below: Mark the pKa on the pH scale and draw which structure predominates at pHs lower and pHs higher than the pKa. Circle the form that predominates at physiological pH (pH = 7.4) 2) Draw the 2 reactions of the weak acid, Carbonic Acid (H2CO3) with water. Which form of carbonic acid predominates at physiological pH? The two pKas of carbonic acid are the following: pKa1 = 6.4 pKa2 = 10.3. 3) You have a 0.1 M solution of HCl in water. HCl is a strong acid. What is the pH of this solution? (Show your work or will not receive credit.) 4) Calculate the pOH of a solution 0.01 M solution of NaOH in water. NaOH is a strong base. What is the pOH of this solution? pOH is defined as: 𝑝𝑂𝐻 = −log [𝑂𝐻−]. (3 pts.) (Show your work or will not receive credit.) 5) Calculate the pOH of the solution in 3) and calculate the pH of the solution in 4). In water the following equation always holds true: 𝑝𝐻 + 𝑝𝑂𝐻 = 14. (Show your work) 6) Write the reaction of trichloroacetic acid with water below. Label the acid, base, conjugate acid, and conjugate base in the reaction you drew. 7) Draw the reaction of the weak base pyridine with water. Label the acid, base, conjugate acid, and conjugate base in the reaction you drew. 8) Decide whether the following molecules are polar or non-polar and which of the 3 intermolecular interactions it has: (London, Dipole-Dipole, Hydrogen Bonding) a. CH3NH2 Polar /// Non-polar London Dispersion /// Dipole-Dipole /// Hydrogen-Bonding b. CH3COOCH3 Polar /// Non-polar London Dispersion /// Dipole-Dipole /// Hydrogen-Bonding c. CCl2F2 Polar /// Non-polar London Dispersion /// Dipole-Dipole /// Hydrogen-Bonding 9) When hydrochloric acid dissolves in water, it forms a strong electrolyte (it produces a strong light in the lightbulb test). Formic acid dissolves in water to form a weak electrolyte (it produces a dim light in the lightbulb test). Use Le Chatelier’s principle to describe why one acid is a weak electrolyte and why one acid is a strong electrolyte.