Question

What does a dark color indicate when using Lugol's iodine?

The presence of starch

The presence of sugar

The absence of starch

The absence of sugar

Answers

GPT-4o mini
A dark color when using Lugol's iodine indicates **the presence of starch**. Lugol's iodine solution reacts with starch to produce a blue-black color. If there is no color change, it indicates the absence of starch.