The student made a mistake in stating that hydrogen has an oxidation number of +1 in the reactant \( H_2 \). In the diatomic molecule \( H_2 \), the oxidation number of hydrogen is 0 since it is in its elemental form. Similarly, the student incorrectly claims that iodine has an oxidation number of -1 in \( I_2 \); like hydrogen, the oxidation number of iodine in \( I_2 \) is also 0 in its elemental state. Since both hydrogen and iodine start at an oxidation state of 0 and end up in \( HI \) with hydrogen at +1 and iodine at -1, there is indeed a change in oxidation states. Therefore, this reaction is a redox reaction, as it involves the oxidation of hydrogen and the reduction of iodine.
Use the chemical equation to complete the activity.H2(g)+I2(g)→2HI(g) A student makes the following statements:Hydrogen always has the same oxidation number, so it has an oxidation number of +1 in both the reactant H2 and product HI .Iodine is in Group VIIA , so it has an oxidation number of −1 in both the reactant I2 and product HI .Neither hydrogen nor iodine changes oxidation states, so the reaction is not a redox reaction.In 3–5 sentences, describe the mistakes that the student made. Based on the oxidation numbers, is this a redox reaction? Explain your answer.
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