What did Peter buy [for] Emma?

[dido4]

Peter bought Emma some beautiful dresses.

Question 1:
What is the original question for the sentence above? Which one is correct?

1. What did Peter buy for Emma?
2. What did Peter buy Emma?

Question 2: Why do we need to use "for" in the question? Or not use "for"?

Thank you.

 

[probus]

1. Both are equally correct and identical in meaning.

2. As the above answer implies, "for" is purely optional. Use it or omit it as you prefer.

 

[BobK]

...but when Emma is made into a pronoun I feel it's more natural to omit the 'for': 'What did you buy her?' (I don't know if there's a rule here: 'What did you buy for her?' is probably OK - it just sounds a bit stilted to me.

 

[BobK]

PS ... unless there's contrastive stress.. "Emma bought me a book for Christmas"/"What did you buy for her?"