Question

Which element increases its oxidation number in this reaction? 2 Na + 2 H₂O → 2 NaOH + H₂

a) Na
b) H
c) O
d) None of the elements increases its oxidation number

Answer 1

The element that increases its oxidation number in the reaction 2 Na + 2 H₂O → 2 NaOH + H₂ is sodium (Na), as its oxidation number increases from 0 to +1.

Step-by-step explanation:

In the reaction 2 Na + 2 H₂O → 2 NaOH + H₂, the element that increases its oxidation number is sodium (Na). In its elemental form, sodium has an oxidation number of 0.

During the reaction, it becomes part of the sodium hydroxide (NaOH) compound, where it has an oxidation number of +1. Thus, the oxidation number of sodium increases from 0 to +1, indicating that sodium is oxidized.

The oxidation number for hydrogen (H) in H₂O is +1 and it remains +1 in H₂, therefore it does not change. Oxygen (O) has an oxidation number of -2 in both H₂O and NaOH, so it also does not change. Therefore, the correct option is a) Na.