Answer:
The oxidation number of hydrogen changes in the reaction 2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g).
We want to identify a change in the oxidation number of hydrogen. We will consider that:
The oxidation number of H in most compounds is +1.
The oxidation number of H in H₂ is 0.
The oxidation number of H in metal hydrides is -1.
In which reaction does the oxidation number of hydrogen change?
2 HClO₄(aq) + CaCO₃(s) → Ca(ClO₄)₂(aq) + H₂O(l) + CO₂(g)
NO. The oxidation number of H in HClO₄ and H₂O is +1.
CaO(s) + H₂O(l) → Ca(OH)₂(s)
NO. The oxidation number of H in H₂O and Ca(OH)₂ is +1.
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
NO. The oxidation number of H in HCl and H₂O is +1.
2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g)
YES. The oxidation number of H in H₂O is +1 whereas in H₂ is 0.
SO₂(g) + H₂O(l) → H₂SO₃(aq)
NO. The oxidation number of H in H₂O and H₂SO₃ is +1.
The oxidation number of hydrogen changes in the reaction 2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g).
Explanation:
