How To Make Adsense Large Leader Board Ads Responsive?



I am trying to add the a responsive adsense ads of size 720x90px on my blog header. I generated the responsive code. But when i add it on my blog the vertical ads are showing. How to make it the size i want.

And, as i know we can display 3 display ads per page but for mobile view what is the limitation of ads per page?

Nee help urgent.