strips the class from the <div> tag in rich text editor

If your class is empty or if your div element is empty, it will remove the class attribute and/or the div element. You have to tell the editor to ignore the empty attributes or elements.

CKEDITOR.dtd.$removeEmpty['div'] = false;

Thanks for quick response.

Where i need to make this changes ?

In the config.js file for the editor where you had already stated you made changes.

/CMSAdminControls/CKEditor/config.js

I try but not going to effect. Same issue yet.

Also there is not any empty tag and class in my html.

before

 <div class="col-md-8">
  <p>Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo.</p></div> <div class="col-md-4"><img src="img/faq-sub.jpg" alt=""></div>

After

<div><p>Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo.</p></div><div></div>

Glad my answer was able to fix your problem.

yes, your answer is also correct but get proper step by step answer from kentico support