"Vera likes orange juice but does not like apple juice."

Translation: Вера любит апельсиновый сок, но не любит яблочный.

[Niels912838]

Why is the use of "а" instead of "но" considered wrong?

[Oberoth-SGA]

You can say this phrase by next ways and the meaning will be almost the same:
Вера любит апельсиновый сок, но не любит яблочный.
Вера любит апельсиновый сок и не любит яблочный.
Вера любит апельсиновый сок, а яблочный не любит.

[AndroidKanada]

Thanks. I'm interested... to use а, you felt you had to rearrange the sentence a bit. Could you comment? Was it to keep апельсиновый сок and яблочный together?

[Oberoth-SGA]

I understand your interest in the last sentence. It really took a lot of time to me to find out a good explanation, but I couldn't. Sorry.
I can only say one thing: Russians never say:
Вера любит апельсиновый сок, а не любит яблочный.
In such sentences they always use conjunction но or и with this words order. And in generally the sentence:
Вера любит апельсиновый сок, но не любит яблочный
is very close by meaning to this one:
Вера любит апельсиновый сок и ненавидит яблочный сок - Vera likes orange juice and hates apple juice.
And finally if you want to use the conjunction а you should use different words order: ..., а яблочный не любит.

[AndroidKanada]

Thanks, that helps somewhat. When the sentence is re-arranged for а, is that to emphasize не любит, the difference?

[Oberoth-SGA]

Yes you're absolutely right.

[Ux.io]

Because "a" is used for stronger emphasis. It is often used to point out that you don't like just this one juice, despite liking all juices. And it just historically happened that idiomatic "a"+[reverse order] is associated with stronger emphasis than "но"

[Leslie509391]

I found this explanation, to which I've added my own examples.

'Но' means that something has occurred is different from the things we expected to happen.  "She likes apple juice but does not like apples."

The ‘A’ conjunction always tells us some new or something different from the things were mentioned before. "She likes apple juice and/but does not like orange juice."

So the main difference between ‘A’ and ‘Ho’ is that ‘A’ is not a contradiction, it simply adds some new information into the conversation, whereas ‘Ho’ is a contradiction to expectations.

Source: https://polyglotclub.com/wiki/Language/Russian/Grammar/%D0%90-vs-%D0%9D%D0%BE

[chsemyonova]

I am wondering the same.

Could someone kindly comment when he/she has the chance?

[AndroidKanada]

I'm also wondering. It's a contrast, thus not «и», and it's not against some obvious expectation, so I'm not expecting «но».

[GranvilleS6]

Why is it wrong to omit the juice 'сок'?. We can in English say either:
Vera likes orange juice but does not like apple juice
or Vera likes orange juice but does not like apple.