Table salt does not turn blue when you squeeze a lemon on top. It is possible that you may be confusing table salt with a different compound or experiencing a chemical reaction with other substances present.
Table salt, or sodium chloride (NaCl), is a white crystalline solid and remains white even when exposed to lemon juice or acidic substances. The color of table salt is not affected by the addition of lemon juice.
However, there are other substances or compounds that can exhibit color changes when in contact with acidic solutions like lemon juice. For example, certain indicators or pH-sensitive compounds can change color in the presence of acids or bases. Phenolphthalein is one such compound that turns pink or magenta in the presence of a base and is colorless in an acidic environment.
If you observe a color change when lemon juice is added to a substance resembling table salt, it may indicate the presence of other compounds or impurities that react with the acid in the lemon juice. It would be helpful to provide more specific details or context if you have observed such a color change, as table salt itself does not exhibit this behavior.