report: 'this question is false' should be added to accepted answers
This question is bad? Should this work as well?
I would say the normal formulation for this idea in English is :
"This is the wrong question"
The phrase : "This question is wrong" I have ever heard in philosophy, science or any other kind of class...
Your formulation is more common but contextually it is perfectly idiomatic English. "Is global warming happening?" This question is wrong. "What is the best response to global warming?" This question is right.
Salah or salahkah?
Salah.. Salahkah is a question word, 'is it wrong ...?'