I have the following TRRS audio female socket meant for audio/stereo headset. As i understand the tip(2) is for left channel, the ring(3) is for right channel, the sleeve(1) is for ground. Now which connection 10 or 11 is used for microphone?
The jack you have shown is a TRS jack, not TRRS.
Terminals 10 and 11 are switch contacts. With no plug inserted, terminal 3 is connected to terminal 11, and 2 is connected to 10. When the plug is inserted, these connections are broken.
If this was used as a headphone jack, the amplifier outputs would be connected to 2 and 3, with internal speakers connected to 10 and 11 - when a plug is inserted, the internal speakers would be disconnected.