Different ways of asking "where" in chinese - zài nǎr or nǎlǐ
Memrise has two very similar phrases
Zhèige fànguǎnr zài nàr (the restaurant is over there)
and
Zhèige fànguǎnr zài nǎr (where is the restaurant)

Is this ok?

Can't I say
Zhèige fànguǎnr zài nǎli? or
Zhèige fànguǎnr nǎli?

When should I use zài?

xièxiè!

Question

Different ways of asking "where" in chinese - zài nǎr or nǎlǐ
Memrise has two very similar phrases 
Zhèige fànguǎnr zài nàr (the restaurant is over there)
and
Zhèige fànguǎnr zài nǎr (where is the restaurant)

Is this ok?

Can't I say 
Zhèige fànguǎnr zài nǎli?  or 
Zhèige fànguǎnr nǎli?

When should I use zài?

xièxiè!

Answer

"na-r" is northern variant, "na-li" is a southern one

Answer

You can use [zai] before direction : east, west, south, north. And location

Answer

you can say (Zhèige fànguǎnr zài nǎli?),but you can't say (Zhèige fànguǎnr nǎli?).you can use 【zai】before the word like:on(在……上面),behind(在……后面)，in(在……里面)，before(在……之前)，where(在哪里)，there,here……and so on