C. Preparation of Solutions in the Basic Range, pH 8 to pH 12 For these start with a high pH solution, 0.01 M sodium hydroxide, NaoH, which is pH 12, and start to work down toward neutral. Dilute 1 mLof the NaoH solution with 9 ml. of the boiled water to make the pH 11 solution. Stir. Similarly prepare solutions of pH 10, pH 9, and pH 8 by progressive tenfold dilutions, just as you did in part 1A. Obtain your assigned indicator (in solution form) from your instructor and add 2 drops of it to each of your prepared solutions and stir. If the color is not distinct, continue to add indica- tor 2 drops at a time to all test tubes. Stir. Label your set, showing the indicator and the num- ber of drops of indicator per test tube. Set it in the designated place in the room. Test tubes need not be stoppered unless they are to be left for use days later. Note and record the color at each pH in all sets of indicators. Notice that there is a continu- ous gradation from each end to the transition zone where the color changes rather of color abruptly. You should be able to locate the point of greatest color change, called the transition point, to the nearest pH unit. The range of greatest color change, from just before to just after this point, is called the pH interval in table A.5.