What would you observe in the following cases: (1) Sodium and potassium are placed in hot water
(ii) Burning magnesium is introduced into steam?
dium and iron with water

See explanation

Explanation:

When introduced to hot water, sodium and potassium metals react violently to form a colourless solution and hydrogen gas. The metal becomes spontaneously ignited and burns with its characteristic flame colour.

Magnesium burns with a bright white flame to yield solid magnesium oxide

and hydrogen gas when steam is passed over heated magnesium.

The last question is not clear but I believe that it has to do with reaction of sodium and iron with water. Sodium reacts violently with cold water at room temperature to evolve hydrogen gas and aqueous sodium hydroxide.

Iron reacts with steam at red heat to yield hydrogen gas and Fe3O4