What is the difference between

ไหม and หรือเปล่า

when asking a yes/no question?

Not much. Usually different ways of asking the same thing.

ไหม is usually translated as "is it " or just a question mark e.g is it hot ?

หรือเปล่า is usually translated as something like is it .. or not, or or not question mark e.g. Is it hot or not ?

ไหม is usually translated as '?'

Chai mai is usually translated as 'is it?'

ruu plow = or not?

ruu yang = yet?

If they both have the same meaning, I'd rather always just say ไหม / มั้ย because it's way easier for me (a native English speaker) to pronounce.

I wonder if Thai people prefer to use หรือเปล่า in certain situations or if it's just random.

If they both have the same meaning, I'd rather always just say ไหม / มั้ย because it's way easier for me (a native English speaker) to pronounce.

I wonder if Thai people prefer to use หรือเปล่า in certain situations or if it's just random.

mai is a question, no pressure

ruu plow is a suggestion with hoped for answer. (I want to do this, how about you)

I always understand "mai" as "?" when the questioner has no idea of the answer, as in "Are you hungry?"

I understand "leur" as "?" when the questioner has already made an assumption about the likely answer, as in "Would you like to eat at MacDonalds?"

I understand "ruu plow" as "or not" as in "Do you want to go to Bangkok or not?"

...... Those are my understandings, but I accept that they might not be 100% accurate. I'm a fluent Thai speaker, but not an academic.

If they both have the same meaning, I'd rather always just say ไหม / มั้ย because it's way easier for me (a native English speaker) to pronounce.

I wonder if Thai people prefer to use หรือเปล่า in certain situations or if it's just random.

mai is a question, no pressure

ruu plow is a suggestion with hoped for answer. (I want to do this, how about you)

You may well be right, but I would use "laow khun la?" for "How about you?"

If they both have the same meaning, I'd rather always just say ไหม / มั้ย because it's way easier for me (a native English speaker) to pronounce.

I wonder if Thai people prefer to use หรือเปล่า in certain situations or if it's just random.

mai is a question, no pressure

ruu plow is a suggestion with hoped for answer. (I want to do this, how about you)

I think to determine whether the person who ask expect for an answer or not, it depends on circumstance. For (funny) example:

My girlfriend asks me "Do you love me?":

คุณรักฉัน หรือเปล่า

คุณรักฉัน ไหม

I feel heavy pressure is on me and I can only say 'Yes'. If not, she will kill me. 555