Answer:
When there is excess of acid the phenolphtalein remains colorless
Explanation:
Hello,
Since, phenolphthalein is naturally colorless, it turns pink in alkaline solutions above pH levels of 8.2 and continues to a bright purple in stronger alkalines since the phenolphtalein is ionized (see attached pictures). In spite of this, below pH levels of 8.2 phenolphtalein is colorless due to the formation of the C-O bond just next to the lower carbonyl group. In such a way, at low pH levels the ionization is shifted rightwards and above 8.2 is shifted leftwards, giving the evidence that when there is excess of acid the phenolphtalein remains colorless.
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