CHEM 1152L Supplemental Lab-Page9 Il. Complex lons - Iron(IlI) thiocyanate Fe3+
ID: 577534 • Letter: C
Question
CHEM 1152L Supplemental Lab-Page9 Il. Complex lons - Iron(IlI) thiocyanate Fe3+ (aq) colorless [Fe(SCN) Dark red (aq) SCN' (aq) colorless + Cap) 1. Write the expression for the equilibrium constant: Predict what happens to the amount of [Fe(SCN) reactant is removed: 2. in solution when one usculd lo isucad is detected by /.red @brir- 3. The [Fe(SCN) 4. Qbservations of solution upon the addition of NaOH: a) Based on your observation, which way does the equilibrium shift when hydroxide ions are added to solution? tao-d the (eactords . b) Explain how your observations indicate this. 5. Observation of solution in hot water bath. tLe Sokuro appea, a Observation of solution in ice bath: -Kr.cotcr of settI+,CA arpa, 'e.. VeN Siu·le Is the reaction exothermic or endothermic? Explain how your observations indicate this. evohanicExplanation / Answer
1. Equilibrium constant = concentration of products/ concentration of products
So, the equilibrium constant of the given reaction is Kc = [Fe(SCN)+2 ]/ [Fe+3 ] * [SCN- ]
2. When one reactant is removed, the equilibrium shifts towards left side, i.e reactant side. So, the amount of the product Fe(SCN)+2 decreases.
3. Fe(SCN)+2 is red dark in colour. So, the appearance of red coloured solution detects the formation of product.
4. Addition of NaOH to the solution of Fe(SCN)+2 produces Fe(OH)3 which is golden yellow in colour and it is obtained as a precipitate. So, you will get a golden yellow precipitate.
a) Based on the observation, it can be concluded that upon addition of base Fe(OH)3 is generated which contains Fe+3 ion. In addition to that SCN- is also produced. So, reactant molecules are generated and the equilibrium shifts to reactant side.
b) Based on the observation, it can be concluded that upon addition of base Fe(OH)3 is generated which contains Fe+3 ion. In addition to that SCN- is also produced. So, reactant molecules are generated and the equilibrium shifts to reactant side.
Fe(SCN)+2 + 3 NaOH = Fe(OH)3 + NaSCN + 2Na+