Bu kimyasal tehlikelidir.

This chemical is dangerous.

Breakdown of Bu kimyasal tehlikelidir.

• olmak: to be
• bu: this
• tehlikeli: dangerous
• kimyasal: the chemical

Questions & Answers about Bu kimyasal tehlikelidir.

What does the suffix -dir do in tehlikelidir?

The -dir suffix is the third-person copula (the equivalent of “is”) in formal/written Turkish. It turns the adjective tehlikeli (“dangerous”) into a complete predicate “(it) is dangerous.” In everyday spoken Turkish you can drop it:
Bu kimyasal tehlikeli.

Why isn’t there a separate word for “is” in the sentence?

Turkish usually expresses “to be” by either suffixing -dir (in writing/formal speech) or omitting it entirely (in informal speech). You don’t use a standalone verb like is.

What part of speech is tehlikeli and how is it formed?

Tehlikeli is an adjective meaning “dangerous.” It’s built from the noun tehlike (“danger”) plus the adjective-forming suffix -li, which turns many nouns into adjectives.

How would you make the sentence negative (“This chemical is not dangerous”)?

Attach the negation değil after the adjective (and before -dir if you keep it):
Bu kimyasal tehlikeli değildir.
In casual speech you usually drop -dir:
Bu kimyasal tehlikeli değil.

How can I ask “Is this chemical dangerous?”