What are the transition elements ? Write two characteristics of the transition elements.
These atoms or ions whose d-orbital are incomplete in ground state or in one of the most common oxidation state are called transition elements or d-block elements. The valence shell electronic configuration of transition elements is (n-1)d¹⁻¹⁰ns¹⁻².
Two characteristics of transition elements :
(i) Transition metals show variable oxidation states.
(ii) All transition metals act as catalyst.
Two characteristics of transition elements :
(i) Transition metals show variable oxidation states.
(ii) All transition metals act as catalyst.
Assign the reason for the following :
Copper (I) ion is not known in aqueous solution.
Explain the following observation :
Most of the transition metal ions exhibit characteristic colour in aqueous solution.
What is meant by ‘disproportionation’ ? Give an example of a disproportionation reaction in aqueous solution.
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number.
How would you account for the following ? Many of the transition elements are known to form interstitial compounds.
When Cu²⁺ ion is treated with KI, a white precipitate is formed. Explain the reaction with the help of chemical equation.
Complete the following chemical equations :
(i) MnO₄⁻(aq) + S₂O₃²⁻(aq) + H₂O(l) →
(ii) Cr₂O₇²⁻(aq) + Fe²⁺(aq) + H⁺(aq) →
(i) Following reactions occur at cathode during the electrolysis of aqueous silver chloride solution :
= +0.80 V
= 0.00 V
On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why ?
(ii) Define limiting molar conductivity. Why conductivity of an electrolyte solution decreases with the decrease in concentration ?
Why a mixture of Carbon disulphide and acetone shows positive deviation from Raoult’s law? What type of azeotrope is formed by this mixture?
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.
State Raoult’s law. How is it formulated for solutions of non-volatile solutes ?
The following curve is obtained when molar conductivity is plotted against the square root of concentration, c½ for two electrolytes A and B :