Learn Spanish (Latin America): Hay una tina blanca en el baño. - There is a white bathtub in the bathroom.

We use hay (there is / there are) because we are talking about the existence of an unspecific object: una tina (a bathtub). If we were talking about where a specific bathtub is located, like "The white bathtub is in the bathroom", we would use a form of estar: La tina blanca está en el baño.

Why is it blanca and not blanco?

In Spanish, describing words (adjectives) have to match the gender of the noun they describe. Because tina is a feminine word (which we can also tell by the word una), the color "white" must be in its feminine form: blanca.

Why does blanca come after tina?

In English, we put the color before the noun ("white bathtub"), but in Spanish, descriptive adjectives usually come after the noun. So, you literally say "a bathtub white" (una tina blanca).

Does en mean "in" or "on"?

It can mean both! The word en is a very flexible preposition that translates to "in", "on", or "at" depending on the context. Here, common sense tells us the bathtub is inside the room, so it means "in the bathroom" (en el baño).