How can I go to the previous desktop in Mission Control using a hot key? Say, I have 10 desktops. I'm on the desktop 2. I switch to the deskotp 7 using the F3 key and touchpad. Is there a standard hot key for switching back to the deskotp 2? And then back to the deskotp 7. 

Similar to Alt+Tab, but for the desktops.
Using keyboard shortcuts to switch Desktops.

Open System preferences > Keyboard > Shortcuts.

Click on the Mission control.

Desktops will show there with number associated to it.

Check all you want to switch.

Use "ctrl" and press number to switch.