Answer:
17.8ml-15.6ml is 2.2 ml then convert to cm so 2.2cm^3
卂几丂山乇尺
As the name indicate that in 1-octene there is a double bond on the first position in the eight carbon atoms chain THUS to detect its presence, we use bromine water test;
Add bromine water to the test tube containing octane/octene if the brown colour of bromine water disappears then octene is present.
Ti2 has 2 unpaired electrons.
Nucleus is the right answer i guess