Chlorine Talk: Acids

Now that we know about chlorine's role as an oxidizer and a disinfectant, it's time to learn about the remainder of it's uses.

Some of you may have heard of chlorine gas, which was used in World War I by both sides against entrenched enemy soldiers. Since chlorine gas is heavier than air, it would sink to the bottom of the trenches, where soldiers would inhale it. Due to chlorine's afore mentioned oxidizing powers, it reacts with the water in their lungs and turned into hydrochloric acid, the strongest acid known to man. I don't believe I need to explain why having acid in your lungs is a bad thing. Now, when you smell the chlorine coming out of your pool, don't worry; while that is chlorine gas, it's not going to kill you. Chlorine gas, (the lethal poison, not gaseous chlorine) is made with a few other key ingredients, and not just be evaporating chlorine; it can be smelled at 3 PPM (Parts Per Million), starts causing coughing and/or vomiting at about 30 PPM, and doesn't cause lung damage until 60 PPM. And even that can be healed. The concentration doesn't become lethal until 1000 PPM.

Back to hydrochloric acid or HCl. But first, we need to know exactly what an acid is. An acid is any substance that is willing to take electrons from another substance that is willing to give electrons. This means that an acid will react with specific substances, known as bases. Lye(Drano) is a commonly known base. During the reaction, the acid and base mix themselves together to create a new substance. And of course, some acids are strong enough to react with materials that aren't normally a base, such as pouring muratic acid (a mix of 30% HCl and 70% water) on concrete. The concrete melts away and mixes with the acid, leaving behind a watery-ish residue that won't react with more concrete.  HCl is also used in toilet bowl cleaner (~3% HCl) and many other solvents.

Other than in chemicals, chlorine is also used in the construction of a lot of plastics, chiefly PVC (Polyvinyl Chloride) and any vinyl materials.

Random Fact: Brain Freeze

I decided to start a new series of posts based on random ideas that will make a small, yet informative post. Look for more random facts in the future!

As you all should know, brain freeze is a small, short lived headache that results from consuming cold food or beverages (e.g. ice cream) really fast. This headache is caused by rapid cooling and rewarming of the blood vessels in the roof of your mouth; heat expansion/contraction causes the blood vessels to dilate, which is detected by the trigeminal nerve, which sends the pain signal back to the brain. This is all pretty simple, just like stubbing your toe; toe gets stubbed, the nerves relay the pain signal back to the brain and you feel said pain in your toe. "But why is pain from the roof of my mouth being felt in my forehead?" An excellent question. See, the trigeminal nerve is one of the primary nerves for detecting facial pain, as a result of this, the brain gets confused and thinks the pain is coming from your forehead.

Incidentally, the same expansion/contraction of blood vessels is what makes your face turn red after being outside on a cold day; this occurrence just doesn't cause pain.