Baking Soda and Vinegar?

How many times have I seen statements or headlines like these?

Of course, we all want a cheap, non-toxic way to clean the house, but is baking soda and vinegar the answer? I put on my science hat and dug in.

Do you recall that unit on acids and bases in your high school chemistry class? If that was a long time ago, here’s a quick and simple refresher.

You know that water is made up of hydrogen (H) atoms and oxygen (O) atoms in a 2 to 1 ratio, hence it’s abbreviated as H2O. What you may have forgotten is that mixed up in this liquid are some loose hydrogen ions (H+). They hook up with water molecules, creating H3O molecules. There are also an equal number of extra OH ions—a pair of atoms missing their extra hydrogen. Because these H+ and OH ions are in balance, the solution is neither acid nor basic. The pH is 7.

How let’s introduce a substance that sheds H+ ions. Suddenly, there are more H+ ions than OH ions, and you have an acid. Acids are solutions with a pH less than 7. The more extra H+ ions there are, the lower the pH and the stronger the acid. One example of a strong acid is hydrochloric acid, which hangs around in your stomach to help digest your meals.

If, on the other hand, you add a substance that collects those extra H+ ions, grabbing them away from the H3O molecules, there will be now be an excess of OH- ions. Now you have a base. Bases are solutions with a pH greater than 7. The more extra OH- ions there are, the higher the pH and the stronger the base. Lye is a very strong base.

Now back to the vinegar and baking soda mixture. Distilled white vinegar is an acid, with a pH around 2.4. (Most brands are diluted until there is 5% acid and 95% water.) It has extra H+ ions. Because it’s an acid, vinegar on its own is handy for cleaning things, like getting rid of hard water scum in the bathroom.

Baking soda is actually sodium bicarbonate, NaHCO3. When dissolved in water, it grabs the H+ ions, creating a surplus of OH ions, so it’s a base. The pH depends on how concentrated a solution you mix up, but it’s likely somewhere between 8 and 9. Because it’s a base, baking soda is also a good cleanser. I’ve used it in place of scouring powder with satisfactory results.

Now, what happens when you combine vinegar and baking soda? The H+ ions in the vinegar react with the sodium and bicarbonate ions in the baking soda. The end result is sodium acetate (C2H3NaO2), carbon dioxide (CO2), and water (H20).

Sodium acetate has a number of uses—medically to replenish electrolytes, as a food additive, in anti-freeze, photographic supplies, and in the manufacturing of concrete, textiles, heating pads, and other industrial processes. However, it doesn’t make a good cleaning agent. In fact, it can irritate your skin, and you should avoid getting it in your eyes.

The carbon dioxide bubbles away, which looks pretty impressive, but, except for the slight scrubbing action of the bubbles, it isn’t likely to clean much of anything. (You may as well just exhale on the dirt!)

Water isn’t that bad at cleaning, even by itself, but why go to all the trouble and expense of combining vinegar and baking soda just to get water?

Mixing vinegar and baking powder may create some pretty impressive foaming action as the two solutions combine. You can use the combination in some exciting and educational home science experiments that the kiddos will love. You can even make a model volcano! (I liked the list of activities at Growing a Jeweled Rose.)

Just don’t expect the combination to be a super cleaning agent.

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