Quick Chemistry Doubt

[AStarHunter]

guyz, got a problem in this paper (http://www.xtremepapers.me/CIE/inde...GCSE/0620 - Chemistry/&file=0620_w06_qp_3.pdf) ---> Q8(c)(iii) ---> how do they know which one is saturated and which one is unsaturated.
Thnx in advance && sorry for my stupidity -.-"

btw, i posted this in another topic but no one seemed to answer me, soooo ... i typed it again ! :lol:

 

[Keeemoman]

OK the first one is unsaturated cause the first one followed the pattern Cn H(2n) which means it is alkene
So this is known by C17 H(17*2) this C17 H34. But since there is a bond so one hydrogen atom is reduced so comes like that -C17 H33

and so vice versa with the next(alkanes)

 

[brainiac]

i think it works like this ..... as we know the functional group for alkenes is Cn H2n and for alkanes it is CnH2n+2 ..... now its simple just put the value (17) in the formula and u will get the answer .... now coming towards the second part so i would like to remind u that whenever the question comes on how to differentiate if a compound is saturated or not ....we use the bromine water test
the results r something like this
unsaturated compound= colour change from brown to colourless is observed
saturated compound= no visible reaction. the colour of the reaction reamins as it is
i hope it helped