Breakdown of Раствор, который находится в колбе, меняет цвет, пока он кипит.
он
he / it (for a masculine noun) / it (for a neuter noun)
цвет
color
в
in / to (direction)
который
which / who / that (relative pronoun)
Questions & Answers about Раствор, который находится в колбе, меняет цвет, пока он кипит.
Why do we use пока here instead of пока не?
Here, пока translates to 'while' because it describes two ongoing actions happening at the same time: the changing of color and the boiling. You would use пока не ('until') if you wanted to say the action continued up to a limit, such as boiling something until it changes color.
Why use the verb находится instead of just saying раствор в колбе (the solution in the flask)?
In English, we often attach location phrases directly to a noun. While раствор в колбе is possible in Russian, it is much more natural and stylistically proper to use a relative clause with находиться (to be located) in descriptive or formal contexts.
How does the aspect of the verbs work with пока in this sentence?
Both меняет (changes) and кипит (boils) are in the imperfective aspect. When you use пока to mean 'while' for two continuous actions happening simultaneously, both verbs must be imperfective.
Is цвет in the nominative or accusative case here?
It is in the accusative case, acting as the direct object of the verb меняет (changes). Because цвет (color) is an inanimate masculine noun, its accusative form looks exactly the same as its nominative dictionary form.