Final answer:
The alkali metals react with water to produce hydrogen gas and a basic solution of the metal hydroxide. The reactivity of alkali metals with water increases as you move down the periodic table. They readily donate their outermost electron to water, resulting in the production of hydrogen gas and metal hydroxide.
Step-by-step explanation:
The alkali metals react with water in a trend. When alkali metals, such as lithium, sodium, and potassium, react with water, they produce hydrogen gas and a basic solution of the metal hydroxide. The reactivity of alkali metals with water increases as you move down the periodic table, with lithium being the least reactive and cesium being the most reactive. For example, the reaction of lithium with water is:
2Li + 2H2O → 2LiOH + H2
This trend can be explained by the fact that alkali metals are easier to oxidize than hydrogen, so they readily donate their outermost electron to water, resulting in the production of hydrogen gas and metal hydroxide.