Question

question 9
in the reaction below, which element is oxidized?
3k(s) + crcl₃(aq) → 3kcl(aq) + cr(s)
○ k
○ cl
○ cr
○ none. this isnt a redox reaction.
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question 10
in the reaction below, which element is oxidized?
mg(s) + ni(clo₄)₂(aq) → mg(clo₄)₂(aq) + ni(s)
○ o
○ cl
○ ni
○ mg
none. this isnt a redox reaction.

Explanation:

Question 9

Step1: Recall Oxidation Definition

Oxidation is loss of electrons (increase in oxidation state).

Step2: Find Oxidation States of K

In \( K(s) \), oxidation state of K is \( 0 \). In \( KCl(aq) \), K has oxidation state \( +1 \) (since Cl is \( -1 \)).

Step3: Check Other Elements

• Cl: In \( CrCl_3 \) and \( KCl \), oxidation state is \( -1 \) (no change).
• Cr: In \( CrCl_3 \), Cr is \( +3 \); in \( Cr(s) \), it's \( 0 \) (reduction, not oxidation).

Step1: Recall Oxidation Definition

Oxidation is loss of electrons (increase in oxidation state).

Step2: Find Oxidation States of Mg

In \( Mg(s) \), oxidation state of Mg is \( 0 \). In \( Mg(ClO_4)_2(aq) \), Mg has oxidation state \( +2 \) (since \( ClO_4^- \) is \( -1 \) per ion, two ions give \( -2 \), so Mg is \( +2 \)).

Step3: Check Other Elements

• O: In \( ClO_4^- \), oxidation state is \( -2 \) (no change).
• Cl: In \( ClO_4^- \), oxidation state is \( +7 \) (no change).
• Ni: In \( Ni(ClO_4)_2 \), Ni is \( +2 \); in \( Ni(s) \), it's \( 0 \) (reduction, not oxidation).

Answer:

A. K

Question 10