Method of continuous variation. Make a graph of absorbance versus mole fraction of thiocyanate from the data in the table.

(a) What is the stoichiometry of the predominant Fe(SCN)_n^3-n species?

(b) Why is the peak not as sharp as those in Figure 18-8?

(c) Why does one solution contain 10.0 mM acid and the other 15.0 mM acid? 

Figure 18-8

Transcribed Image Text:

mL Fe3 solution 30.00 27.00 24.00 21.00 18.00 15.00 12.00 9.00 6.00 3.00 mL SCN solution 3.00 6.00 9.00 12.00 15.00 18.00 21.00 24.00 27.00 30.00 Absorbance at 455 nm 0.001 0.122 0.226 0.293 0.331 0.346 0.327 0.286 0.214 0.109 0.002 2