Question

question 37 (5 points)
for the reaction
no(g) + kmno₄(aq) → mno₂(s) + kno₃(aq)
which element is reduced?

1. permanganate

which ion is a spectator ion?

1. nitrogen

what is the oxidizing agent?

1. manganese

what is the reducing agent?

1. nitrogen monoxide
2. potassium

which element is oxidized?

Explanation:

To solve this, we analyze the oxidation states:

Step 1: Determine Oxidation States

• N in NO: Oxidation state of O is -2. Let N be \( x \): \( x + (-2) = 0 \) → \( x = +2 \).
• Mn in \( \text{KMnO}_4 \): K is +1, O is -2. Let Mn be \( y \): \( +1 + y + 4(-2) = 0 \) → \( y = +7 \).
• Mn in \( \text{MnO}_2 \): O is -2. Let Mn be \( z \): \( z + 2(-2) = 0 \) → \( z = +4 \).
• N in \( \text{KNO}_3 \): K is +1, O is -2. Let N be \( w \): \( +1 + w + 3(-2) = 0 \) → \( w = +5 \).
• K (potassium): In \( \text{KMnO}_4 \) and \( \text{KNO}_3 \), K remains +1 (no change).

1. Which element is reduced?

Reduction = gain of electrons (decrease in oxidation state). Mn goes from \( +7 \) (in \( \text{KMnO}_4 \)) to \( +4 \) (in \( \text{MnO}_2 \)) → manganese (option 3).

2. Which ion is a spectator ion?

Spectator ion: No change in oxidation state. K (potassium) remains +1 in \( \text{KMnO}_4 \) and \( \text{KNO}_3 \) → potassium (option 5).

3. What is the oxidizing agent?

Oxidizing agent: Species that is reduced (causes oxidation of another species). \( \text{KMnO}_4 \) contains \( \text{MnO}_4^- \) (permanganate ion), and Mn is reduced here → permanganate (option 1).

4. What is the reducing agent?

Reducing agent: Species that is oxidized (causes reduction of another species). NO (nitrogen monoxide) has N oxidized from +2 to +5 → nitrogen monoxide (option 4).

5. Which element is oxidized?

Oxidation = loss of electrons (increase in oxidation state). N in NO goes from \( +2 \) to \( +5 \) (in \( \text{KNO}_3 \)) → nitrogen (option 2).

Final Answers:

1. Which element is reduced? \(\boldsymbol{3}\) (manganese)
2. Which ion is a spectator ion? \(\boldsymbol{5}\) (potassium)
3. What is the oxidizing agent? \(\boldsymbol{1}\) (permanganate)
4. What is the reducing agent? \(\boldsymbol{4}\) (nitrogen monoxide)
5. Which element is oxidized? \(\boldsymbol{2}\) (nitrogen)

Answer:

To solve this, we analyze the oxidation states:

Step 1: Determine Oxidation States

• N in NO: Oxidation state of O is -2. Let N be \( x \): \( x + (-2) = 0 \) → \( x = +2 \).
• Mn in \( \text{KMnO}_4 \): K is +1, O is -2. Let Mn be \( y \): \( +1 + y + 4(-2) = 0 \) → \( y = +7 \).
• Mn in \( \text{MnO}_2 \): O is -2. Let Mn be \( z \): \( z + 2(-2) = 0 \) → \( z = +4 \).
• N in \( \text{KNO}_3 \): K is +1, O is -2. Let N be \( w \): \( +1 + w + 3(-2) = 0 \) → \( w = +5 \).
• K (potassium): In \( \text{KMnO}_4 \) and \( \text{KNO}_3 \), K remains +1 (no change).

1. Which element is reduced?

Reduction = gain of electrons (decrease in oxidation state). Mn goes from \( +7 \) (in \( \text{KMnO}_4 \)) to \( +4 \) (in \( \text{MnO}_2 \)) → manganese (option 3).

2. Which ion is a spectator ion?

Spectator ion: No change in oxidation state. K (potassium) remains +1 in \( \text{KMnO}_4 \) and \( \text{KNO}_3 \) → potassium (option 5).

3. What is the oxidizing agent?

Oxidizing agent: Species that is reduced (causes oxidation of another species). \( \text{KMnO}_4 \) contains \( \text{MnO}_4^- \) (permanganate ion), and Mn is reduced here → permanganate (option 1).

4. What is the reducing agent?

Reducing agent: Species that is oxidized (causes reduction of another species). NO (nitrogen monoxide) has N oxidized from +2 to +5 → nitrogen monoxide (option 4).

5. Which element is oxidized?

Oxidation = loss of electrons (increase in oxidation state). N in NO goes from \( +2 \) to \( +5 \) (in \( \text{KNO}_3 \)) → nitrogen (option 2).

Final Answers:

1. Which element is reduced? \(\boldsymbol{3}\) (manganese)
2. Which ion is a spectator ion? \(\boldsymbol{5}\) (potassium)
3. What is the oxidizing agent? \(\boldsymbol{1}\) (permanganate)
4. What is the reducing agent? \(\boldsymbol{4}\) (nitrogen monoxide)
5. Which element is oxidized? \(\boldsymbol{2}\) (nitrogen)