Ii n desuka vs Ii desu ka

Please help me understand the difference between "Ii n desu ka?" and "Ii desu ka?" I learnd that "Ii n desu ka?" means "Is it OK with you?" So, I said to my Japanese friend "Raishuu asobini ikimasu. Ii n desu ka?" Then, she said that I need to say "Ii desu ka?" I do not understand why "n" is skipped. Thank you .

This little "n" thing is difficult to explain... but "n" is often used to refer to something already talked about before.

So, if you are asking for permission, "ii desu ka?" (since it's the first time you are mentioning it) would be correct. For example to give you an extreme example, if she says yes you can come, you can come evern at 6 am (an early time) you might say, surprised, "iin desu ka?" (Really? Is THAT ok?)

Normally "ii desu ka?" is the standard expression for "is it OK?" (asking for permission).

I have tried asking Japanese about this one before, needless to say, they seemed quite unable to explain it.

I learned that using 'n' is sometimes even considered to be rude, because it conveys a certain feeling of curiosity from the speaker, which in some formal situations might not be a good thing.

Thank you very much AK & D.