Final answer:
The question pertains to using the activity series to predict if single-replacement chemical reactions will occur, which is a concept within high school chemistry. It involves comparing reactivities of elements to determine the feasibility of the reactions.
Step-by-step explanation:
The subject of the question is chemistry, specifically related to chemical reactions and the activity series. The activity series is a list of elements ordered by their ability to displace other elements in single replacement reactions, which can be used to predict the outcomes of such reactions.
In single-replacement reactions, one element replaces another element in a compound. Whether a reaction will occur can be predicted using the activity series. For a reaction to proceed, the single element must be more reactive than the element it is trying to replace. For instance, if we have the reaction Al(s) + Zn(NO3)2 (aq) →, we would note that aluminum (Al) is more active than zinc (Zn). Therefore, a reaction will occur and the balanced chemical equation would be 2Al(s) + 3Zn(NO3)2 (aq) → 3Zn(s) + 2Al(NO3)3 (aq).
Another example is Ag(s) + HCl(aq) →. Since silver (Ag) is less reactive than hydrogen (H), a reaction will not occur, and we would write NR (no reaction).