Which of the following ions will always be a spectator ion in a precipitation reaction? (a) Cl- (b) NO3- (c) NH4+ (d) S2- (e) SO42-

Video transcript

Welcome back everyone to another video which of the following ions will always be a spectator ion in a precipitation reaction. A chloride anion B nitrate anion C barium cion D carbonate anion and E lead to cion. We got five answer choices which basically correspond to the previously indicated choices. Now, let's think about this problem in terms of solubility rules. Let's start with a chloride anion. And let's remember that according to the solubility rules, the majority of chlorides are soluble except from, let's say as an example, silver chloride, we know that this is a precipitate, right? Or we can also take lead two chloride. This is also a precipitate as well as mercury two chloride. OK. So what we know is that if chloride anion can form precipitates, then it will not necessarily be a spectator ion all the time because iron Spectators are a result of a reaction in which we can actually cancel them out and they are not forming a precipitate in an ionic compound. Now, let's think about nitrates and according to the solubility rules, we can say that all nitrates are soluble. In other words, it doesn't really matter what kind of a cion we take whenever we form a salt with nitrate, such as salt will be soluble in water. So B is our first candidate for the correct answer, right? We want to label it so far. Now C we have barium Canion and in this case, let's simply remember our classical precipitate barium sulfate. It's a solid, right? It's white precipitate. It's a group to two A element which forms precipitates with sulfates and carbonates. Herbarium cannot always be a spectator iron because it forms insoluble salts. D carbonate. Once again, a lot of carbonates are soluble. But as previously indicated, we can have barium carbonate for instance, which is a solid, right group. Two A elements tend to form in soluble carbonates. We can also take calcium carbonate, which is a classical example. And as a result due to the fact that carbonate can form insoluble told it will not necessarily be an honest spectator. Now, e led to cion, we already know that lead can form lead to chloride, which is insoluble at lower temperatures, right? Or for example, lead to sulfate because those are solids. Let two cion is unlikely to be an iron spectator. So the only option from this list is nitrate, it will always act as a spectator ion. And we can conclude that the correct answer to this problem is option B nitrate anion is likely to be a spectator iron or more accurately speaking, it will always be a spectator iron in a precipitation reaction. Thank you for watching.