Final answer:
To distinguish between sodium bicarbonate and sodium phosphate, you can add an acid (like hydrochloric acid) to the powder. Sodium bicarbonate will produce carbon dioxide and water, evident by bubbling, while sodium phosphate will not.
Step-by-step explanation:
To determine whether a white powder is sodium bicarbonate or sodium phosphate, specific chemical tests involving reactions with acids and observing different precipitates can be conducted. For instance, adding barium chloride to a solution of the test salt may form a white precipitate, indicating the presence of a sulphate or carbonate. However, both sodium bicarbonate and sodium phosphate can form a white precipitate with silver nitrate, so this test alone is insufficient.
One definitive test is to add an acid, like hydrochloric acid, to the unknown powder. Sodium bicarbonate will react with the acid producing carbon dioxide gas, water, and the corresponding sodium salt, which can be observed as effervescence (bubbling). Sodium phosphate, on the other hand, will not produce such effervescence with dilute acids. Conducting this reaction in a controlled environment, such as a laboratory with proper safety measures, can effectively differentiate between the two compounds.