These are two words we use frequently in daily conversation. so what is the difference between 何か and 何が。 Consider the following situation,
When you return home hungrily and asking your mother,
You : 何か食べ物ありますか？(Is there any food? or is there anything to eat?)
Here you don't know whether there is something to eat. So you are asking, is there anything to eat?. For this question the answer is either yes or no.
Mother : はい、(Yes)
You: 何があります？(What is there?
Here your mother said there is something to eat. So you want to know what are all the food available?
Summary:
なにか - anything or something?
なにが - what?
何があります and 何がありますか
Usually in spoken language, the speaker mostly do not use ka(か) when he is asking なにがあります？ and use ka(か)when they ask なにかありますか. In fact this is purely speaker specific and this is not a rule. and some people make it as question by intonation
But the proper grammar is always use ka(か)to make the statement as question.
so it would be なにがありますか？
