1-To the third portion of the agar solution saved from experiment 1, and while still hot, add and mix well: a trace of potassium ferrocyanide solution, few drops of dilute sodium hydroxide, and a few drops of phenolphthalein. Notice that a pink color develops in the mixture as a result of the reaction between the sodium hydroxide and the indicator (ph.ph).2-Pour out the mixture in test tubes to half capacity, stand the tubes upright in refrigerator to set the gel. Mark the level of agar in the tube.3-Add few ml of dilute ferric chloride solution to each tube, keep some tubes at room temperature (25C), and place the other tubes in the refrigerator at 10C .Notice that the pink color disappears gradually from the top downwards, and a dark blue color appears at the top and proceeds downwards. Record the distance of change in color, explain the results and comment.

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Somebody is playing a trick on you. There is no past tense in the imperative mood.