Which of the following is most likely to be an active ingredient in common household bleach? A) NaCl, B) NaClO, C) NaHCO₃, D) Na₂SO₄, or E) HC₂H₃O₂.
Bleach is a common household product known for removing stains from materials. Much of the time when we have a stain on our clothes, it’s due to a molecule that has a conjugated system of double bonds, which is a long chain of consecutive double bonds. This long chain of consecutive double bonds is able to absorb light. So, we perceive that molecule as being colored. Household bleaches work by either breaking the double bonds or by replacing them with single bonds. Bleaches that break up the double bonds are called oxidizing bleaches. And bleaches that convert the double bond into a single bond is called a reducing bleach.
Either way, the effect is the same. There’s no more system of connected double bonds. So, the molecule can’t absorb light anymore. So, we don’t perceive they’re being any more colored stain. Household bleaches are basically always oxidizing bleaches, so we’ll focus on those. Like the name suggests, oxidizing bleaches are made of oxidizing agents, which are chemical species that can oxidize other chemical species but they get reduced. Now, let’s see if we can figure out which of the following chemical species is most likely to be the active ingredient in household bleach.
First, let’s identify the name of each of these species. Answer choice A is NaCl which is sodium chloride. Sodium chloride is definitely a household product, though not something that’s contained in bleach as sodium chloride is simply table salt. Table salt isn’t much use in removing stains, so it’s not the answer we’re looking for. Answer choice B is sodium hypochlorite. Sodium hypochlorite is known for being a powerful oxidizing agent, so this is likely the chemical species that we’re looking for. Our next answer choice is sodium bicarbonate or sodium hydrogen carbonate, which is also a common household product, as it’s also known as baking soda. Though baking soda can be useful for cleaning, it’s not generally associated with bleaching things.
Our next answer choice is sodium sulfate. Sodium sulfate is a neutral salt since the sulfate anion is the conjugate base of the strong acid, sulfuric acid. Our final answer choice is acetic acid or ethanoic acid. It’s also a common household product as this is the chemical species that’s found in white distilled vinegar. Of our answer choices, sodium hypochlorite is the only one that’s known for being a strong oxidizing agent. And, in fact, sodium hypochlorite is the primary ingredient in most household bleaches.