Is Na2O an acid or a base

Oxides and water - acid or base?

(Although this is not a portal specifically for homework, we are traditionally happy to help if someone has already thought about homework themselves.)

As hellosydney69 said, it is mostly (!) That non-metal oxides form acids and metal oxides form bases.

At Non-metal oxides a water molecule is usually attached. Here

- the water splits into H and OH
- an oxygen double bond of the non-metal oxide becomes a single bond
- The H is attached to the oxygen atom with the new single bond on the other side
- the OH is attached to the central atom

Using the example of SO₂:

O = S = O

H - O - H

becomes

And that is usually represented as

H
|
O
|
O = S
|
O
|
H

In Cl₂O₇ the Cl-O-Cl bonds tend to be very unstable. (According to Wikipedia, this connection is even explosive.) This applies to pretty much all elements of the 7th main group and the lighter elements of the 6th main group. Therefore, one of the bonds can easily be broken and a water molecule inserted in between.

At Metal oxides an oxygen ion O²⁻ is usually given off to the water, which reacts immediately with water to form 2 OH Ionen ions. Using the example of Na₂O:

Na⁺ O²⁻ Na⁺ (no binding lines, because of ionic bond)

H
|
O - H

becomes

Na⁺ O⁻ Na⁺
|
H

O⁻ - H

(Some metals bind the oxygen atoms in their oxides so tightly that they can also form acids; the best-known examples are zinc and aluminum. One then speaks of amphoteric metal oxides. But that should only be of interest for later. If the examples are mentioned in the exam that you mentioned, you don't need to expect these special cases there.)