How to place blocks in bootstrap from left and right margins?

Question

Bootstrap

There are 2 blocks in the nav tag, one from the left edge and the second from the right, but when the screen narrows at 720px, they become one after another, what should be done so that they do not collapse? It should be on any extension like this: but now like this

<nav class="nav">
       <div class="col-lg-8 col-md-7 col-sm-6 col-xs-6">contant</div>
       <div class="col-lg-4 col-md-5 col-sm-6 col-xs-6">contab</div>
</nav>

Bootstrap4

Answer 1

Can you give an example of how you do it and the version of the bootstrap?