Suggest reasons for the following features of transition metal chemistry :
(i) The transition metals and their compounds are usually paramagnetic.
(ii) The transition metals exhibit variable oxidation states.
(i) The transition metals and their compounds are usually paramagnetic.
(ii) The transition metals exhibit variable oxidation states.
(i) Due to presence of unpaired electrons in d-orbitals.
(ii) Due to incomplete filling of d-orbitals. Due to very small energy difference in between (n-1) d and n s-orbitals.
(ii) Due to incomplete filling of d-orbitals. Due to very small energy difference in between (n-1) d and n s-orbitals.
Explain the following :
(i) The enthalpies of atomization of transition metals are quite high.
(ii) The transition metals and many of their compounds act as good catalysts.
Explain the following observation :
Most of the transition metal ions exhibit characteristic colour in aqueous solution.
How would you account for the following ? Many of the transition elements are known to form interstitial compounds.
What are the transition elements ? Write two characteristics of the transition elements.
(i) Account for the following :
(a) Cu⁺ is unstable in an aqueous solution.
(b) Transition metals form complex compounds.
(ii) Complete the following equation :
CrO₂₇²⁻ + 8H⁺ + 3NO₂⁻ →
Account for the following :
(i) CuCl₂ is more stable than Cu₂Cl₂.
(ii) Atomic radii of 4d and 5d series elements are nearly same.
(iii) Hydrochloric acid is not used in permanganate titration.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
Following reactions can occur at cathode during the electrolysis of aqueous silver nitrate solution using Pt electrodes:
In the following ions:
Mn³⁺, V³⁺, Cr³⁺, Ti⁴⁺
(Atomic no: Mn = 25, V = 23, Cr = 24, Ti = 22)
(a) Which ion is most stable in an aqueous solution?
(b) Which ion is the strongest oxidizing agent?
(c) Which ion is colourless?
(d) Which ion has the highest number of unpaired electrons?
Calculate the degree of dissociation (α) of acetic acid if its molar conductivity () is 39.05 Scm² mol⁻¹. Given (H⁺) = 349.6 Scm² mol⁻¹ and (CH₃COO⁻) = 40.9 Scm² mol⁻¹..
Suggest reasons for the following features of transition metal chemistry :
(i) The transition metals and their compounds are usually paramagnetic.
(ii) The transition metals exhibit variable oxidation states.
The following curve is obtained when molar conductivity is plotted against the square root of concentration, c½ for two electrolytes A and B :