what are difference between meaning of these sentences please?
1_他买什么？
他在买什么呢？

2- 我去商店。
我在去商店呢。

Question

what are difference between meaning of these sentences please?
1_他买什么？
    他在买什么呢？

2- 我去商店。
    我在去商店呢。

Answer

1_他买什么？ = What does he buy?
他在买什么呢？ = What is he buying?

2- 我去商店。 = I go to the shop.
我在去商店呢。 = I'm on my way to the shop.

Answer

1_他买什么？(what is he buying.the point is "what")
他在买什么呢？(by this way to ask,the point is not "what",this question is more like:what is he doing.

2- 我去商店。(the answer of"where are you going to? )
我在去商店呢。(more like the answer of"where are you?"you tell them i am on the way to a store.

Answer

我在[去商店的路上]。or 我[要]去商店。makes more sense than 在去