[johnsy123]

Cervonic acid is a polyunsaturated fatty acid found in fish oil. The number of carbon-carbon double bonds in a mole of cervonic acid can be determined by titration with iodine, I2, solution. An addition reaction takes place between the double bonds in cervonic acid and iodine.

20.00ml of 0.300M I2 solution reacted exactly with 0.328 of cervonic acid. The molar mass of cervonic acid is 328.0gmol.

i) calculate the number of double bonds in a molecule of cervonic acid.
ii)There are 22 carbon atoms in the molecule of cervonic acid. What is the formula of cervonic acid?


-I worked out question i to be be 6 double bonds, but i am a little stuck on how to get the formula in question ii.

[AWK]

Start from a balanced reaction. Use variable at iodine.

[Vidya]

Now you know that degree of unsaturation is 6
use this formula  to get H atoms
 (2#C + 2 - #H )/2 = 6
this will give you you number of H with 22 C
remaing is due to  O

[sjb]

Now you know that degree of unsaturation is 6
use this formula  to get H atoms
 (2#C + 2 - #H )/2 = 6
this will give you you number of H with 22 C
remaing is due to  O

Just be careful, as the unsaturation is not solely due to C=C here.