How does TCP connection terminate if one of the machine dies?

Question

If a TCP connection is established between two hosts (A & B), and lets say host A has sent 5 octets to host B, and then the host B crashes (due to unknown reason). The host

Answer 1

Depends on the OS implementation. In short it will wait for ACK and resend packets until it times out. Then your connection will be torn down. To see exactly what happens in Linux look here other OSes follow similar algorithm.