How to hide sidebar in single post detail?

Hello everyone,

its quite simple, yet I cant figure this out. How can I please hide siderbar while looking into blog post?

I have a blog post list, I open one of them and on the right side sidebar appears. I found the widgets it contains, but after deleting them (category list, archive,…) others just pop up, but these are not being displayed in the “Widgets” list. It must be loading from the demo… I need to restrict sidebar view in this particular page (generally for all posts).

Thanks for help in advance!