Question

1. choose the best answer.

_____ is the process in which an atom or ion experiences an increase in oxidation state.
reduction
equation
oxidation
conservation

1. choose the best answer.

which type of reaction is this?
pb(no₃)₂(aq) + 2ki(aq) → 2kno₃(aq) + pbi₂(s)
precipitation
redox
acid - base

Explanation:

Question 10

To solve this, we recall the definitions of the terms:

• Reduction: Decrease in oxidation state (gain of electrons).
• Equation: A representation of a chemical reaction, not related to oxidation state change.
• Oxidation: Increase in oxidation state (loss of electrons).
• Conservation: Related to conservation laws (like mass, charge), not oxidation state change.

So the process with an increase in oxidation state is oxidation.

Analyze the reaction $\ce{Pb(NO_{3})_{2}(aq) + 2KI(aq) -> 2KNO_{3}(aq) + PbI_{2}(s)}$:

• Precipitation reaction: A reaction where an insoluble solid (precipitate) forms from aqueous solutions. Here, $\ce{PbI_{2}(s)}$ is a solid precipitate formed from aqueous reactants.
• Redox reaction: Involves change in oxidation states, which is not seen here (oxidation states of $\ce{Pb}$, $\ce{N}$, $\ce{O}$, $\ce{K}$, $\ce{I}$ remain same).
• Acid - base reaction: Involves transfer of $\ce{H+}$ or $\ce{OH-}$, which is not the case here.

So this is a precipitation reaction.

Answer:

C. Oxidation

Question 11