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Name: Jenny Status: student Grade: 9-12 Location: Outside U.S. Country: Canada Date: Winter 2013-14

Question:
Hello, this might be a stupid question but I have been searching everywhere trying to find the difference. Is there a difference between HYDROCHLORIDE AND HYDROCHLORIC ACID? The reason I ask is because I read hydrochloric acid is harmful to dogs and humans and in the ingredients on my dog's food, there is hydrochloride, I am just a worried mom, i don't want to be feeding him food with harmful chemicals in it.

Replies:
Hello Jenny,

It's an interesting point you bring up, hydrochloride and hydrochloric acid are easy to confuse, and part of the reason for this is how closely related the two terms are. Hydrochloric acid HCl, is a strong, monoprotic acid. This means that it can be very dangerous at high concentrations (acid burns, irritation from inhalation/exposure to fumes, etc.). Hydrochlorides (chemicals listed as "*chemical name* hydrochloride") are usually organic molecules which have been treated with hydrocloric acid to make them more soluble. This process renders the molecule a positively charged salt in an ionic bond to the negative Cl- ion lent by the HCl. If a label says something about a chemical name, it really just means that it's been treated in this manner to make it soluble in water. Hydrochloric acid is certainly dangerous, but the chemical engineers who did the treatment of your hydrochloride chemical have taken care of the dangerous part. Acids are generally only considered acutely toxic, meaning that overexposure during a short period can result in severe burns and irritation. If your dog shows signs of drool, a red or inflamed mouth, abscesses, or ulcerative lesions, these could all be accounted for by exposure to a strong acid. However, low levels of hydrochloride found in most foods shouldn't be anywhere near strong enough to cause any of these symptoms.

Sincerely, Rick Armstrong


That's not a stupid question at all.

First and foremost, I have no idea what ingredients may or may not be harmful to your pet. But just because an ingredient is called a "hydrochloride" does not mean that it contains hydrogen chloride, otherwise known as hydrochloric acid or muriatic acid.

Without seeing the ingredient list it is difficult to be sure, but I suspect that the phrase "hydrochloride" is just after the name of some other formula name, like "glucosamine hydrochloride" or "betaine hydrochloride." In both cases these compounds do not literally contain hydrochloric acid, just like carbohydrates do not literally contain water molecules even though they are "hydrates." Instead, these are salts in which the first compound gets an "extra" proton (H+) and a negatively charged chloride ion is in the crystal to balance things out charge-wise.

For those who know some chemistry, consider solid NH4Cl, which everyone calls ammonium chloride. It consists of NH4+ (ammonium) cations and Cl- (chloride) anions. However, if you imagined transferring an H+ from the NH4+ to the Cl- within the solid (which does not happen in reality), you could call it ammonia hydrochloride (NH3 is ammonia). The naming convention that is used in the food and drug industries is to name the chloride salts of protonated amines as "hydrochlorides."

Just to summarize; hydrochlorides are salts made of a molecule with an extra proton and a chloride ion. They don't contain any HCl molecules. Many medicines and nutritional supplements are sold as hydrochlorides, because they are more readily absorbed by the body in protonated form.

best wishes, Prof. Topper


Hi Jenny,

Your question has significant relevance! The short answer is: it depends. Hydrochloric acid(HCl) is harmful to living matter if concentrated. However, we have dilute HCL in our stomach to initiate protein digestion!

In processed foods, supplements and pharmaceuticals, reactive amines(a base) are neutralized using HCl, forming a stable salt. This helps with stability and shelf life. The FDA requires that although the HCl has little pharmaceutical action, it must be reported on the label. These have been tested and are regarded as safe for human(and animal) consumption.

If your dog food is produced by a reputable vendor - the hydrochloride is a salt, not an acid, you and your dogs should be just fine.

Peter E. Hughes, Ph.D. Milford, NH


I am happy to answer this one. Hydrochloric acid (HCl) is indeed harmful as it exist as a free acid. If we breath in the fumes or get it into our bodies it will harm us. Realize however that dilute hydrochloric acid is a part of our and most animal's digestion process since it is found in a weak strength in our stomach. In the weak state, it helps break down food. It is essential. Understand that really depends on the strength of it, and that strength is measured in pH. When some form of HCl is combined with a base, it forms a salt. In the case of what you are seeing on the dog/cat food is a salt of the reaction of some HCl with a base. The compound formed is a hydrochloride. This hydrochloride or salt of hydrochloric acid is OK and not harmful. It is a relatively neutral salt. Most animal food contains pyridoxine hydrochloride which is Vitamin B6. In a similar fashion, if we react sulfuric acid with a base a salt will also result; so called sulfate. We see sulfates in foods as preservatives.

So, do not worry about hydrochlorides as they appear in animal foods. I applaud your attention to labels. I wish more people would take the time. Additionally, you could always call the company that makes the product and ask them.

Best regards ====================== Stephen R. Dunn Ass't Professor of Medicine (ret.) Dept. Medicine/ Div. Nephrology & Cancer Genomics Kimmel Cancer Center Thomas Jefferson University


Hydrogen chloride is a gas. When dissolved in water it becomes hydrochloric acid. About 432 grams of hydrogen chloride gas is dissolved in water to make a 1 liter of concentrated hydrochloric acid. Such concentrated forms of hydrochloric acid are used in industrially and is extremely corrosive and toxic. Dilute forms of the acid are sold in hardware stores as Muriatic Acid. They are reserved for industrial use only. Emissions of hydrogen chloride or hydrochloric acid are regulated by the Environmental Protection Agency.

Hydrochloric acid in very dilute form ( extremely dilute , almost 100 times less dilute than concentrated hydrochloric acid) is part of gastric juices secreted in digestion of food. However, this type of acid is produced by the body naturally.


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