2.5.5 variable oxidation states

how do transition metals form ions

lose the 4s electron before the 3d

what happens to the relative stability of the +2 state with respect to the +3 states across the period

increases

what do compounds with high oxidation states tend to be

oxidising agents

e.g. MnO₄^-

what do compounds with low oxidation states tend to be

reducing agents

e.g. V²⁺ and Fe²⁺

what influences the redox potential for a transition metal changing from a higher to lower oxidation state (2)

pH

ligand

what is the oxidation state and colour of VO₂⁺

+5

yellow

what is the oxidation state and colour of VO²⁺

+4

blue

what is the oxidation state and colour of V³⁺

+3

green

what is the oxidation state and colour of V²⁺

+2

violet

what is the reduction half equation for Tollens reagent

[Ag(NH₃)₂]⁺ + e^- ——> Ag + 2NH₃

what is the oxidation half equation for Tollens reagent

CH₃CHO + H₂O ——> CH₃CO₂H +2H⁺ + 2e^-

what is the redox titration equation between manganate and iron (II)

MnO₄^-_(aq) + 8H⁺ _(aq) + 5Fe²⁺_(aq) ——> Mn²⁺ _(aq) + 4H₂O _(l) + 5Fe³⁺_(aq)

why is this titration self indicating

there is a significant colour change

purple to colourless

what type of acid should you use for manganate titrations only

dilute sulfuric acid

what is the ratio between moles of manganate and moles of iron

1:5

manganate : iron

what is the moles ration between ethanedioate and manganate

5:2

ethanedioate : manganate

what is the mole ratio between iron ethanedioate and manganate

5:3

iron ethanedioate : manganate