In a solution of a certain substance, the litmus color turned red. From the formulas of the substances

In a solution of a certain substance, the litmus color turned red. From the formulas of the substances, select the formula for the possible substance: 1) KOH2) NA₂SO₄3) H₃PO₄

Litmus is a natural substance that changes its color depending on the environment it gets into. The medium is divided into neutral (the number of hydrogen ions in the solution is equal to the number of hydroxyl groups (H + 1 = OH-1), acidic (H + 1 is more than OH-1) and alkaline (H + 1 is less than OH-1). number 3 is phosphoric acid, in solution it dissociates into hydrogen ions H + 1 and ions of the acid residue PO43-. Since there are many hydrogen ions in the solution, the medium becomes acidic, the litmus turns red.