Question

1. choose the best answer.

_____ reactions involve the formation of an insoluble solid.
redox
precipitation
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

Explanation:

Question 19

• Redox reactions involve electron transfer (oxidation - reduction), not insoluble solid formation.
• Precipitation reactions are defined by the formation of an insoluble solid (precipitate) from aqueous solutions.
• Acid - base reactions involve proton (H⁺) transfer, forming water and a salt, not necessarily an insoluble solid.

• The reaction is $\ce{H_{2}SO_{4}(aq) + 2NaOH(aq) -> Na_{2}SO_{4}(aq) + 2H_{2}O(l)}$.
• $\ce{H_{2}SO_{4}}$ is an acid, $\ce{NaOH}$ is a base. They react to form a salt ($\ce{Na_{2}SO_{4}}$) and water, which is the characteristic of an acid - base (neutralization) reaction.
• Precipitation reactions form an insoluble solid, and this reaction has no precipitate. Redox reactions involve electron transfer (change in oxidation states), which is not seen here (oxidation states of S, Na, O, H remain the same).

Answer:

B. Precipitation

Question 20