"Waar is deze grote rode knop voor?"
Translation:What is this big red button for?
We do exactly the same in English, but to a lesser extent--usually in historical or more formal texts.
At elevated temperatures the metal decomposes nearly all other metallic oxides, wherefore it is most serviceable as a metallurgical reagent.
- What is it most serviceable for?
Wherefore art thou Romeo?
- What are you Romeo for?
But wherefore have you scorned my counsel, and come into peril?
- What have you scorned my counsel for?