How many pages are good for an author in writing a sole chapter, and why?

There are no standards.

On the extreme ends, William Gibson’s The Peripheral is about 128,000 words and 124 chapters, making each chapter a bit over 1,000 words on average. Some of the chapters are quite a lot shorter; there are chapters that are a page and a half. On the other hand, Terry Pratchett wrote books with no chapter breaks at all; the entire book is one chapter.

You do whatever works for your story. That’s the thing about being a writer: you decide. It’s your book, your story, your world. Don’t look to other people to tell you what to write.

The chapters in the books I write vary from about 2,000 words to about 3,500 words, generally speaking. However, the far-future post-Collapse magical realism novel I’m working on with my Talespinner is 16 chapters of about 10,000 words each, so the chapters are significantly longer than an average novel’s.

Your book, your story, your world. Do what your book requires.

If you want to publish, get in the habit of thinking in terms of words, not pages.