Final answer:
The flame color when lithium reacts with water and ignites is bright crimson, a characteristic specific to lithium due to its unique emission spectrum.
Step-by-step explanation:
The color of the flame when lithium ignites, such as in a reaction with water, is a bright crimson. Alkali metals like lithium react vigorously with water to form hydrogen gas and a basic solution of the metal hydroxide. During this reaction, as lithium is oxidized, it emits a characteristic crimson color in its flame, which is part of its emission spectrum. This is in contrast to sodium, which imparts a bright yellow color to a flame. The process by which different elements emit specific colors when heated is a widely used technique in chemistry to identify substances through flame tests.
Lithium creates a bright, crimson color when it ignites. This is because the alkali metals, such as lithium, impart color to a flame. The other alkali metals create a pale, violet color.