16. A 0.500M solution of ascorbic acid (vitamin C) has a pH of 2.20. Find the Ka of ascorbic acid. (3) 17. The chemical responsible for the brown color of photochemical smog is nitrogen dioxide. Nitrogen dioxide is a fairly unstable molecule, that exists in the following equilibrium with colourless dinitrogen tetraoxide: 2NO2(g)N2O4(g)H=57.20kJ/mole a. A scientist takes an air sample from downtown Toronto during the winter at 0C, and finds the following equilibrium concentrations: [N2O4]=1.8107. [NO2]=5.59105. What is the Keq for this reaction at 0C?(1) b. During the summer, the same scientist collects another air sample at 25C and finds the following equilibrium concentrations: [N2O4]=4.0106, [NO2]=7.78104. What is the Keq for this reaction at 25C?(1) c. What do your results from (a) and (b) suggest about when smog would be at its worst? What explains the difference in the equilibrium between summer and winter? (3)