Final answer:
The acid H3PO3 is known as phosphorous acid. H3PO4 is phosphoric acid, and it forms crystal with several uses, including being an additive in soft drinks. It's crucial to distinguish between the similar compounds H3PO3 and H3PO4.
Step-by-step explanation:
The student has asked for the name of the acid with the formula H3PO3. This compound is known as phosphorous acid. However, there seems to be a confusion with H3PO4, which is phosphoric acid. It is important to note the difference between these two compounds. Phosphoric acid is an oxyacid with three acidic protons and can form various compounds, such as dihydrogen phosphate (H₂PO₄-), which is also a weak acid.
Pure orthophosphoric acid, which is H3PO4, forms colorless, deliquescent crystals that melt at 42 °C and is often found in an 82% syrupy form used in a variety of applications, including as an additive in soft drinks. When naming oxyacids like these, the -ate ending in the oxyanion base name is followed by 'ic' plus 'acid' for the acid form.