I am having LG smart tv 42LB6500 which have audio out by digital audio optical only , HDMI port is also available in it and my Sony home theatre is having ARC input but when I connecting it, sound is not coming in home theator speaker.
Your TV supports ARC on the HDMI 1 input only so that is where you need to connected it. On most TVs you have to turn it on in one of the menus and select that source in your Sony.