Which of the following common liquids would likely have the highest pH level when tested, indicating it is more basic?

The liquid that would most likely show the highest pH is a baking‑soda solution or a mild soap solution, both of which are strongly basic. In a pH test, these liquids give values around 9–10, much higher than neutral water (pH 7) or acidic drinks like vinegar (pH 3) or lemon juice (pH 2). The reason is that baking soda (sodium bicarbonate) and soap contain alkaline ions that neutralize acids, raising the pH. For example, dissolving a teaspoon of baking soda in a cup of water produces a pH close to 9, clearly more basic than plain tap water.