Question

1. choose the best answer.

_____ reactions involve the formation of an insoluble solid

• precipitation
• redox
• acid - base

1. choose the best answer.

which type of reaction is this?
$\ce{h_{2}so_{4}(aq) + 2naoh(aq) -> na_{2}so_{4}(aq) + 2h_{2}o(l)}$

• precipitation
• acid - base
• redox

1. choose the best answer.

which type of reaction is this?
$\ce{cl_{2}(g) + 2fe(aq) -> 2cl^{-} + 2fe^{3+}}$

• redox
• acid - base
• precipitation

Explanation:

Question 17

Precipitation reactions are defined by the formation of an insoluble solid (precipitate). Redox reactions involve electron transfer (oxidation - reduction), and acid - base reactions involve proton (H⁺) transfer (neutralization). Since the question is about reactions forming an insoluble solid, precipitation is the correct type.

The reaction \( \ce{H_2SO_4(aq) + 2NaOH(aq) -> Na_2SO_4(aq) + 2H_2O(l)} \) is a neutralization reaction. In this reaction, sulfuric acid (an acid) reacts with sodium hydroxide (a base) to form a salt (sodium sulfate) and water. Precipitation reactions form a solid precipitate, and redox reactions involve changes in oxidation states. Here, there is no solid precipitate formed, and no change in oxidation states, so it is an acid - base reaction.

In the reaction \( \ce{Cl_2(g) + 2Fe(aq) -> 2Cl^- + 2Fe^{3+}} \), we can check the oxidation states. The oxidation state of Cl in \( \ce{Cl_2} \) is 0, and in \( \ce{Cl^-} \) it is - 1 (reduction). The oxidation state of Fe is 0 in the reactant and + 3 in \( \ce{Fe^{3+}} \) (oxidation). Since there is a transfer of electrons (oxidation and reduction occurring simultaneously), this is a redox reaction. Acid - base reactions involve proton transfer, and precipitation reactions form a solid precipitate, neither of which is the case here.

Answer:

A. Precipitation

Question 18