Final answer:
Group I metals react with hydroxides to form hydroxides and hydrogen gas, which is characteristic of the formation of bases, option B.
Step-by-step explanation:
When group I metals, also known as alkali metals, react with hydroxides such as OH-, Ca(OH)2, Sr(OH)2, and Ba(OH)2, the reaction does not form acids. Instead, these reactions typically result in the formation of hydroxides and hydrogen gas, which indicates the B) Formation of bases. Group I metals are highly reactive with water and other acids, often releasing a significant amount of heat during the reaction. For example, when group 1 metals react with water, the typical reaction is the formation of metal hydroxide and hydrogen gas, as seen with lithium:
2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)
This reaction is exothermic and quick. The alkali and more active alkaline earth metals, such as calcium, strontium, and barium, react similarly with water, underlining their nature as reducing agents and further validating that they form basic solutions when reacting with hydroxides.