Will the iOS 8 be on the iPhone 4?

Will the iOS 8 be on the iPhone 4?

It will depend if the hardware is able to run it

No,

Compatible list on the bottom of this page:
https://www.apple.com/...e.com/ios/ios8/" class='ext_link'>https://www.apple.com/.../ios/ios8/
in the future, use this link instead:
https://www.apple.com/ios/