Sodium hydrogen carbonate (NaHCO₃), also known as baking soda, has a slightly alkaline pH in solution.

Here's why:

* Hydrolysis: When NaHCO₃ dissolves in water, it undergoes hydrolysis, meaning it reacts with water molecules. This reaction produces bicarbonate ions (HCO₃⁻) and hydroxide ions (OH⁻).

* Hydroxide ions: The presence of hydroxide ions (OH⁻) is what makes the solution alkaline.

* pH range: The pH of a sodium bicarbonate solution typically falls between 8 and 9, depending on the concentration.

Important Note: The exact pH of a sodium bicarbonate solution can vary slightly depending on factors like temperature and the presence of other dissolved substances.