How to say "What is red?"

[aiwprton]

Hello everybody,
I've just started learning Japanese about two weeks ago and wanted some help with this: If someone said "赤です" and I had no idea what that person was talking about and would like to ask "What is red?", how would I ask that? I've read that it would be "赤は何ですか". But that confuses me. Why would the は come after the 赤? Wouldn't the topic rather be the 何, since that is the thing I want to know about? So could I ask something like "何が赤ですか"?
Thanks in advance.

 

[Toritoribe]

Yes, 何が赤ですか is correct.

 

[aiwprton]

Yes, 何が赤ですか is correct.

Thanks a lot! Does that mean, the first sentence is incorrect? If not, is one of them preferred?

 

[Toritoribe]

赤は何ですか can't be used in your situation.

 

[aiwprton]

赤は何ですか can't be used in your situation.

Would 赤は何ですか mean, that I want know what the word 赤 means?

 

[Toritoribe]

There are some things whose color you don't know about, and you are asking what red one is among them.

 

[aiwprton]

There are some things whose color you don't know about, and you are asking what red one is among them.

I thought that would be "どれが赤ですか". Is that the same?

 

[Toritoribe]

赤いのはどれですか is the most common. 赤は何ですか can be the second question or the later, if it's used.

この中で、青いのはどれですか？
これです。
じゃあ赤は何ですか？(Even in this situation, どれですか is more common.)