sodium bicarbonate

American  

noun

Chemistry, Pharmacology.

1. a white, crystalline, water-soluble solid, in powder or granules, NaHCO 3 , usually prepared by the reaction of soda ash with carbon dioxide or obtained from the intermediate product of the Solvay process by purification: used chiefly in the manufacture of sodium salts, baking powder, and beverages, as a laboratory reagent, as a fire extinguisher, and in medicine as an antacid.

---

sodium bicarbonate British  

noun

1. Also called: bicarbonate of soda.   baking soda.  a white crystalline soluble compound usually obtained by the Solvay process and used in effervescent drinks, baking powders, fire extinguishers, and in medicine as an antacid; sodium hydrogen carbonate. Formula: NaHCO 3

---

sodium bicarbonate Scientific  

1. A white crystalline compound used in beverages and as a leavening agent to make baked goods. In medicine, sodium bicarbonate is used as an antacid and cleanser and to replenish electrolytes. Also called baking soda, bicarbonate of soda. Chemical formula: NaHCO ₃ .

---

Closer Look

A white, chalky powder, sodium bicarbonate also goes by its household name, baking soda. Sodium bicarbonate is a base and reacts with acids in what is called neutralization, because both the acid and the base are converted into more neutral substances on the pH scale. Neutralization with sodium bicarbonate usually produces carbon dioxide gas, which bubbles forth whenever vinegar (an acid) and baking soda are mixed (as they frequently are in “kitchen science” experiments). Such reactions are an important factor in baking, where the production of the gas is what causes cakes to rise. Sodium bicarbonate has long been used in small amounts (about a half teaspoon) mixed with water to neutralize excess stomach acid. Sodium bicarbonate also has the unique ability to neutralize substances that are more basic than it is. It can do this because in water, sodium bicarbonate breaks down ultimately into carbonic acid (H₂CO₃), an unstable acid, which can then react with a base to neutralize it. This ability to neutralize both acids and many bases is why baking soda is so effective at reducing odors.

Etymology

Origin of sodium bicarbonate

First recorded in 1880–85

Compare meaning

How does sodium-bicarbonate compare to similar and commonly confused words? Explore the most common comparisons:

• sodium carbonate vs. sodium bicarbonate

Example Sentences

The rise of Nomio follows a recent surge in the use of sodium bicarbonate, also known as plain-old baking soda.

From The Wall Street Journal • Feb. 12, 2026

Westminster Coroners’ Court heard Elena Ali and Sunny Parker-Propst were both given sodium nitrite instead of sodium bicarbonate in 2020 while under the care of staff at Chelsea and Westminster Hospital.

From BBC • Jul. 22, 2024

There is some limited evidence that combining ketones and sodium bicarbonate supplements could counteract this.

From Salon • Oct. 3, 2023

Vinegar is acetic acid, and baking soda contains sodium bicarbonate, a base.

From National Geographic Kids • Oct. 22, 2014

If there is hyperacidity of the stomach, sodium bicarbonate or milk of magnesia will be of benefit.

From Disturbances of the Heart by Osborne, Oliver T. (Oliver Thomas)