If you have 1 row and 2 columns both col-6 i.e. taking equal halves of the screen. Put a responsive image in there which takes up the full with. On the right slide, make the image slide left onto the screen, and do the opposite for the opposite side.
When in mobile view you will notice the right side whitespace from the animation, remove the animation or even change it to slide-right and the whitespace goes. Make sure you have pressed f12 and gone into mobile mode.
Took me HOURS of wasted time figuring out why my website had whitespace tho I was using all the responsive guidelines.
Let me know if a repro project is needed.