are they correct?

[Student33]

Are the following correct?

1.Do you know the package in which this was?
2.Do you know the package which this was in?
3. Do you know the place where the boys were?
4.The place where the boys were was a scary one.

[OddThomas]

We would most likely sayDo you know which package this was in?
And if the boys were lostDo you know which place the boys were?
Or if you don't have to use which placeDo you know where the boys were?
But sentence 3 raises an interesting point. If we wanted to find out if the other person was familiar with the place, we would askDo you know the place where the boys were?
The difference is whether the boys were truly lost, or were somewhere known to us but maybe not to our conversation partner. Do you know the place means are you familiar with it, do you know about it?

The place where the boys were was a scary one is correct.

[Student33]

But are they correct as they are?
I am not asking for equivalents but are they correct grammatically?

[OddThomas]

All four are grammatically correct. That does not mean that they achieve your intended purpose. Nor does it mean that they are coherent thoughts. My horse is raining is grammatically correct, but it is nonsense.

Number 4 is a good sentence.

Numbers 1-3 while correct, are awkward and somewhat confusing ways to say what may be on your mind. Your listener is likely to respond with What? or Huh?

Number 1 and number 2 ask whether I know something of or about the package. They don't really ask if I know which package contained the item, which I believe is what you are trying to ask.

Number 3 I've already analyzed. It doesn't truly ask, Do you know where the boys went?