Question

decide whether each chemical reaction in the table below is an oxidation - reduction (
edox\) reaction. if the reaction is a redox reaction, write down the formula of the reducing agent and the formula of the oxidizing agent.
2n₂(g)+5o₂(g)→2n₂o₅(g)
feo(s)+co(g)→fe(s)+co₂(g)
2ca(s)+o₂(g)→2cao(s)

Explanation:

Step1: Determine oxidation - states

For the reaction $2N_2(g)+5O_2(g)\to2N_2O_5(g)$: In $N_2$, the oxidation - state of $N$ is $0$, in $O_2$ the oxidation - state of $O$ is $0$, and in $N_2O_5$, the oxidation - state of $N$ is $+ 5$ and of $O$ is $-2$. Since there is a change in oxidation states, it is a redox reaction. The reducing agent is the substance that gets oxidized. Here, $N_2$ is oxidized (its oxidation state increases from $0$ to $+5$), so the reducing agent is $N_2$. The oxidizing agent is the substance that gets reduced. Here, $O_2$ is reduced (its oxidation state decreases from $0$ to $-2$), so the oxidizing agent is $O_2$.

Step2: Analyze second reaction

For the reaction $FeO(s)+CO(g)\to Fe(s)+CO_2(g)$: In $FeO$, the oxidation - state of $Fe$ is $+2$ and of $O$ is $-2$, in $CO$ the oxidation - state of $C$ is $+2$ and of $O$ is $-2$, in $Fe$ the oxidation - state of $Fe$ is $0$, and in $CO_2$ the oxidation - state of $C$ is $+4$ and of $O$ is $-2$. Since there is a change in oxidation states ( $Fe$ is reduced from $+2$ to $0$ and $C$ is oxidized from $+2$ to $+4$), it is a redox reaction. The reducing agent is $CO$ ( $C$ is oxidized), and the oxidizing agent is $FeO$ ( $Fe$ is reduced).

Step3: Analyze third reaction

For the reaction $2Ca(s)+O_2(g)\to2CaO(s)$: In $Ca$, the oxidation - state of $Ca$ is $0$, in $O_2$ the oxidation - state of $O$ is $0$, and in $CaO$ the oxidation - state of $Ca$ is $+2$ and of $O$ is $-2$. Since there is a change in oxidation states ( $Ca$ is oxidized from $0$ to $+2$ and $O$ is reduced from $0$ to $-2$), it is a redox reaction. The reducing agent is $Ca$ ( $Ca$ is oxidized), and the oxidizing agent is $O_2$ ( $O$ is reduced).

Answer:

For $2N_2(g)+5O_2(g)\to2N_2O_5(g)$:
redox reaction? yes
reducing agent: $N_2$
oxidizing agent: $O_2$

For $FeO(s)+CO(g)\to Fe(s)+CO_2(g)$:
redox reaction? yes
reducing agent: $CO$
oxidizing agent: $FeO$

For $2Ca(s)+O_2(g)\to2CaO(s)$:
redox reaction? yes
reducing agent: $Ca$
oxidizing agent: $O_2$