Can I use the USB-C Apple adapter, to charge my MacBook 12', with USB-A port?
No, this will not work.  You cannot charge through the USB-A port.  

The USB-A port is a 3.0 port which will supply 5V of power, but it will not be able to negotiate to receive power per the USB 3.1 spec.

Per the Multiport AV Adapter specifications:


  Use the standard USB port to connect devices such as your flash drive
  or camera, or a USB cable for syncing and charging your iPhone, iPad
  or iPod. You can also connect a charging cable to the USB-C port to
  charge your Mac.