Which of the following are redox reactions? For those that are, indicate which element is oxidized and which is reduced. For those that are not, indicate whether they are precipitation or neutralization reactions. (a) P4(s) + 10 HClO(aq) + 6 H₂O(l) → 4 H₃PO₄(aq) + 10 HCl(aq) (b) Br₂(l) + 2 K(s)→ 2 KBr(s) (c) CH₃CH₂OH(l) + 3 O₂(g) → 3 H₂O(l) + 2 CO₂(g) (d) ZnCl₂(aq) + 2 NaOH(aq) → Zn(OH)₂(s) + 2 NaCl(aq)

Verified step by step guidance

1. Identify the oxidation states of each element in the reactants and products.
2. For the reaction P4 + 10 HClO + 6 H2O -> 4 H3PO4 + 10 HCl, determine the oxidation state of phosphorus (P) in P4 and in H3PO4.
3. Determine the oxidation state of chlorine (Cl) in HClO and in HCl.
4. Check if there is a change in oxidation states for any element. If there is a change, identify which element is oxidized (increase in oxidation state) and which is reduced (decrease in oxidation state).
5. If no change in oxidation states is observed, classify the reaction as either a precipitation or neutralization reaction based on the reactants and products.

Key Concepts

Redox Reactions

Redox reactions, or reduction-oxidation reactions, involve the transfer of electrons between two species. In these reactions, one substance is oxidized (loses electrons) while another is reduced (gains electrons). Identifying the oxidation states of elements before and after the reaction helps determine which species undergo these changes.

Oxidation and Reduction

Oxidation refers to the process where an atom or ion loses electrons, resulting in an increase in oxidation state. Conversely, reduction is the gain of electrons, leading to a decrease in oxidation state. Understanding these definitions is crucial for identifying which elements are oxidized and reduced in a given reaction.

Types of Reactions

Chemical reactions can be classified into various types, including precipitation, neutralization, and redox reactions. Precipitation reactions involve the formation of an insoluble solid from two aqueous solutions, while neutralization reactions occur between an acid and a base, producing water and a salt. Recognizing these categories helps in analyzing the nature of the reaction presented.