conclusion

Physical Properties:

(1). It is colourless, has no odour and is neutral.
(2). It is slightly soluble in water.
(3). It has almost the same density as air.
(4). It freezes at 54K.
(5). It has a boiling point of 90K at 1 atmosphere pressure (i.e. 760 mm Hg).
(6). It is very active and reacts with many metals and non-metals to form basic and acidic oxides respectively.

Basic oxide - examples include MgO, Na₂O and CaO;
Acidic oxide - examples are CO₂, SO₂ and P₄O₁₀ (acidic oxides of non-metal are also called acid anhydrides).