Here's why:

* Chemical Structure: TSP is a salt formed from the reaction of phosphoric acid (H₃PO₄) and sodium hydroxide (NaOH). The resulting compound, Na₃PO₄, has a pH greater than 7, making it alkaline (basic).

* pH Scale: The pH scale ranges from 0 to 14, with 7 being neutral. Acids have a pH less than 7, while bases have a pH greater than 7.

* Action: TSP's cleaning power comes from its ability to break down grease and grime by saponifying (turning into soap) fats and oils.

While TSP is a powerful cleaner, it can be harsh on certain surfaces and can cause skin irritation. Always use it with caution and follow safety guidelines on the product label.