what is that building? - >is correctEnglish
But it's a different question, structure-wise.
Mikä rakennus tuo on? - What building is that?
Mikä tuo rakennus on? - What is that building?
English speakers would say, What is that building? Not, what building is that?
Can tuo be interchangeable like :
Mikä tuo rakennus on ? Or
Mika rakennus tuo on ?
It gives which as a translation but you can't use it?
What kind of building is that ???
That would be Millainen rakennus tuo on? :)