Final answer:
To achieve a good yield of hydrate or gem-diol, the presence of water, a catalyst, and favorable conditions for hydrogen bonding are necessary. Electrolysis of water yields pure H2(g), while hydrates such as cobalt (II) chloride contain significant water in their structure, impacting their color and mass.
Step-by-step explanation:
To obtain a good yield of hydrate or gem-diol, certain conditions and reactants are more favorable. Gem-diols are formed from carbonyl compounds (aldehydes or ketones) when there's sufficient water and the presence of an acid or base catalyst to facilitate the reversible addition of water across the carbonyl group, leading to hydrogen bonding. However, since the reaction is in equilibrium, pure carbonyl compounds without bulky substituents are more likely to be hydrated. In contrast, for producing high-quality hydrogen gas (H2(g)), electrolysis of water (H2O(l)) is one of the purest methods, albeit it's not commercially viable due to the high amount of energy required.
Regarding hydrates, compounds like cobalt (II) chloride exhibit distinct colors when hydrated and anhydrous. Hydrates contain water within their crystal lattice, contributing significantly to their mass, often up to nearly half. These hydrates can convert to an anhydrous form upon heating, illustrating the importance of water in their crystal structure and the dynamic nature of their composition.