Floating columns

I have a page with 7 rows, each row has two equally sized columns which are set through the theme's shortcode. I need to float the left column in row 1, 3, 5 and 7 right, but I can't get this to work. The HTML is

    <div id="content" class="container">
    <div class="row">
    <div class="main col-md-12" id="spmain" role="main">
    <div class="entry-content" itemprop="mainContentOfPage">
    <div class="row"> <div class="col-md-6  ">
    <div class="square_2" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">...</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_1" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">....</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_2" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">...</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_1" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">...</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_2" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">...</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_1" style="text-align: center;">...</div>
    </div><div class="col-md-6  ">...</div></div>
    <div class="row"> <div class="col-md-6  ">
    <div class="square_2" style="text-align: center;"></div>
    </div><div class="col-md-6  ">...</div></div>
    </div>

If I use .col-md-6{float:right;}, every column is floated but I just need the left column in row 1,3,5, and 7.

via Chebli Mohamed