What happens when calcium and potassium are put in water?

When calcium and potassium are placed in water, they react differently due to their distinct chemical properties:

Calcium (Ca):

Calcium is a highly reactive alkaline earth metal. When it is placed in water, it undergoes a vigorous exothermic (heat-releasing) reaction.

Calcium reacts with water to produce calcium hydroxide (Ca(OH)2) and hydrogen gas (H2) according to the following chemical equation:

2Ca(s) + 2H2O(l) -> 2Ca(OH)2(aq) + H2(g)

The result of this reaction is the formation of a cloudy, white suspension of calcium hydroxide in the water, and bubbles of hydrogen gas are released. The calcium hydroxide is only slightly soluble in water and will settle as a solid precipitate over time.

Potassium (K):

Potassium is an alkali metal and is even more reactive than calcium. When potassium is placed in water, it undergoes a highly exothermic reaction that is more violent compared to calcium's reaction.

Potassium reacts with water to produce potassium hydroxide (KOH) and hydrogen gas (H2) as shown in the following chemical equation:

2K(s) + 2H2O(l) -> 2KOH(aq) + H2(g)

This reaction is so vigorous that it may result in a small explosion, with the liberated hydrogen gas igniting due to the heat generated. Potassium hydroxide is a strong base and dissolves completely in water.

In summary, when calcium is placed in water, it reacts to form calcium hydroxide and hydrogen gas, while potassium undergoes a more violent reaction, forming potassium hydroxide and hydrogen gas. The reactions with both metals release hydrogen gas, which is flammable and can potentially ignite in the case of potassium. These reactions demonstrate the reactivity of alkaline earth metals (like calcium) and alkali metals (like potassium) with water.