Question

3. In this experiment, you will determine the [FeSCNP at equilibrium by measuring its absorbance at - 450 nm. This is possible due to which of the following statements? Fe+ (aq) + SCN (aq) FeSCN2+ (aq) a. Fe and SCN do not absorb significantly at 450 nm. b. At equilibrium, only FeSCN* is present in the solution. c. [Fe] and [SCN) are too small to absorb light. d. The equilibrium constant, Keq, is small. 4. Give the names for the ions. a. Fe²+ Iron (11Dion b. SCN Thiocyanate ion 5. Circle the piece(s) of glassware that would be used to make 100 mL of 0.005 M NaCl from a stock solution of 0.1 M NaCl? 50 mL volumetric flask • 5 mL volumetric pipet 25 mL volumetric pipet 100 mL volumetric flask

Answer 1

3) Answer is a).

Both Fe3+ and SCN- don't absorb radiation whereas Fe(SCN)2+ absorb radiation due to d-d transition.

4) a) Iron(III) ion

b) Thiocyanate ion

5) Answer is 5 ml volumetric pipet and 100 ml volumetric flask.

Using, M1V1 = M2V2

0.1×V1 = 0.005×100

V1 = 0.5/0.1 = 5 ml

Hence, 5 ml solution was pipet out in 100 ml volumetric flask and diluted to 100 ml.