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.