Tris is a commonly used buffer in biochemistry. It works well in the neutral to slightly basic pH range. A working solution of Tris?HCl buffer was made by mixing equal volumes of Tris base solution (made by dissolving 0.1454 g of Tris base in 50 mL of deionized water) with HCl solution (made by adding deionized water to 4 mL of 0.1 M HCl until the volume was 50 mL). The working buffer solution was warmed to 30 ?C and the pH of this solution was determined to be 8.03. What is the pKa of Tris under these conditions?