Colour of transition metal complexes

The table shows the observed colour of three octahedral complex ions formed by the same metal ion, $\ce{M^{2+}}$, with different ligands. Complex ion Colour of complex $\ce{[MF6]^4-}$ green $\ce{[M(H2O)6]^2+}$ blue $\ce{[M(NH3)6]^2+}$ yellow Which statement…

Portions of the rinse water were then titrated with the standardized EDTA solution in the presence of murexide as indicator. The burette readings are given in the table. Trial 1 Trial 2 Trial 3 Trial 4 Final burette reading / $\mathrm{cm^3}$ (± 0.05…

The cyanide ion acts as a ligand in many complex ions, for example hexacyanoferrate(III), $\ce{[Fe(CN)6]^3-}$. (i) State the type of bond, as precisely as possible, that joins each cyanide ion to the iron ion. (ii) Deduce the oxidation state of iron in…

Each indicator contains more than one benzene ring. (i) State one functional group, other than the phenyl group, that is present in all three indicators. (ii) Deduce the colour of light absorbed by bromothymol blue in acidic conditions and by bromophenol blue…

Draw a line of best fit on the graph, extrapolating it beyond the range of the data.

State, in mathematical terms, how the absorbance of these solutions depends on their concentration.

The colorimeter can record either absorbance or percentage transmittance at a chosen wavelength. Outline why one particular wavelength has to be selected.

Deduce the equation that relates absorbance to concentration for these solutions, including the numerical value of the constant.

Estimate the absorbance of a 0.400 $\mathrm{mol\,dm^{-3}}$ solution of nickel(II) sulfate.

Predict the difference, if any, between the absorbance of the 0.400 $\mathrm{mol\,dm^{-3}}$ solution read from the extrapolated line and the value calculated from the equation in 3d.

Nickel(II) sulfate solution is green. Deduce the most suitable wavelength for this colorimetry, using section 15 of the data booklet.

In the first step, manganese(III) ions formed from the manganate(VII) are complexed by ethanedioate ions. $\ce{[Mn(H2O)6]^3+(aq) + 2C2O4^2-(aq) -> [Mn(C2O4)2(H2O)2]^-(aq) + 4H2O(l)}$ (i) Deduce the oxidation state of carbon in $\ce{[Mn(C2O4)2(H2O)2]^-}$. (ii)…

An aqueous solution of nickel(II) sulfate, which contains the $\ce{[Ni(H2O)6]^2+}$ ion, is green. Which statement explains the origin of this colour? A. Red light is absorbed when electrons are promoted between the split d orbitals of the nickel ion. B. Red…

Anhydrous nickel(II) chloride is yellow, whereas magnesium chloride is white. (i) State nickel's condensed electron configuration. (ii) In terms of electron configuration, state why nickel(II) chloride is a coloured compound. (iii) Nickel(II) chloride absorbs…

Aqueous nickel(II) ions, $\ce{[Ni(H2O)6]^2+}$, appear green. Which statements correctly account for this colour? I. Red light is absorbed when an electron is promoted from the lower to the higher set of split d-orbitals. II. Green light is emitted when…

Which ion is likely to form a coloured aqueous solution, based on its electron configuration? A. $\ce{Ag+}$ B. $\ce{Ti^4+}$ C. $\ce{Cd^2+}$ D. $\ce{Cr^3+}$

Chloride ions can act as ligands towards transition metal ions. Three compounds of chromium that differ in the number of chloride ions bonded directly to the chromium ion have the formulas and colours shown. Compound Colour $\ce{[Cr(H2O)6]Cl3}$ violet…

Aqueous solutions of nickel(II) sulfate, which contain $\ce{[Ni(H2O)6]^2+}$ ions, are green. Use section 15 of the data booklet. Which statement explains the colour? A. Green light is absorbed when an electron is promoted between the split 3d orbitals. B.…