The reaction of calcium with water is less violent compared to potassium and sodium. While it also produces metal hydroxide and hydrogen gas, the heat evolved is not sufficient for the hydrogen to catch fire.

Potassium and sodium react violently with cold water, producing metal hydroxide and hydrogen gas. The reaction is so exothermic that the evolved hydrogen immediately catches fire.

Additional reactions such as reactions with acids, displacement reactions, or reactions with other reactive substances can help establish the order of reactivity among metals like zinc, iron, copper, and lead. These reactions provide clearer indications of the relative reactivity of ...

Burning in oxygen may not provide conclusive evidence of the reactivity of metals like zinc, iron, copper, or lead because these metals may not react with oxygen under normal conditions or may form oxides that are not easily distinguishable.

The reactivity of metals like zinc, iron, copper, and lead can be determined by observing their reactions with various reagents or solutions, such as acids or displacement reactions with more reactive metals.

The thick oxide layer formed during anodising can be easily dyed, allowing aluminum articles to be colored in various shades. This capability to dye the oxide layer gives aluminum articles an attractive finish, enhancing their aesthetic appeal.

In anodising, a clean aluminum article is made the anode and is electrolysed with dilute sulfuric acid. Oxygen gas is evolved at the anode and reacts with aluminum to form a thicker protective oxide layer.

Aluminum naturally develops a thin oxide layer when exposed to air, which acts as a protective barrier, making it resistant to further corrosion.

Anodising is a process of forming a thick oxide layer on the surface of aluminum. Its purpose is to enhance the corrosion resistance of aluminum and provide a durable and attractive finish.

Silver and gold do not react with oxygen even at high temperatures because they are relatively unreactive metals and do not readily form oxides under normal conditions.