Question

i just need some guidance. if someone could do 1 of the calculations with a bit of an explanation that would be great. thanks

1. Calculate the Kovat's retention index for the following compounds that were separated on a polar column at 100° C. Remember to show the formula you have used as well as all your work. Compound Adjusted Retention Time (minutes) Carbon Tetrachloride 3.99 Undecane 8.43 Pentene 7.72 Octane 4.98 Xylene 8.22 Hexane 2.87 Heptanol 3.31 Nonane 6.10 Heptane 3.44 Propyne 5.41 Decane 7.89 Cyclohexane 6.31

Answer 1

Kovads Retention index, I = 100 [n+ (N-1) log to Cunknown) - logtr ] : log to N - log tom) n number of corobon atorms in the smalles n- alkane. Ny number of carton odoms in the larger n-alkane. to Retention time. Let us proceed with the first compound. 2 Carbon tetra chloride. Longest alkane is Decane undecane and shortest is hexcane. not n=6, N=11

do cechy to = 3.99. min. = 2.87 min = 8.43. to (N ..I = 100 (6 + 11-6 log (3.9) - log & 87 log (8.43) - log (2.87 752.9 753 ..For Carbon tetra chlonde , I = 753. The same procedure is used for finding I for remain other compounds.