Explain the following observations:
(i) Copper atom has completely filled d orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element.
(ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solution.
(i) Copper atom has completely filled d orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element.
(ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solution.
(i) Because it has incompletely filled d orbitals in one of its oxidation state (Cu²⁺).
(ii) Cr²⁺ (d⁴) changes to Cr³⁺ (d³) while Fe²⁺ (d⁶) changes to Fe³⁺ (d⁵). In aqueous medium d³ is more stable than d⁵ .
(ii) Cr²⁺ (d⁴) changes to Cr³⁺ (d³) while Fe²⁺ (d⁶) changes to Fe³⁺ (d⁵). In aqueous medium d³ is more stable than d⁵ .
Explain the following observation :
(i) Silver atom has completely filled d-orbitals (4d¹⁰) in its ground state, yet it is regarded as a transition element.
(ii) E° value for the Mn³⁺/Mn²⁺ couple is much more positive than Cr³⁺/Cr²⁺
Explain the following observation :
Most of the transition metal ions exhibit characteristic colour in aqueous solution.
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.
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.
What is meant by ‘disproportionation’ ? Give an example of a disproportionation reaction in aqueous solution.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
Assign the reason for the following :
Copper (I) ion is not known in aqueous solution.
How many electrons flow when a current of 5 amps is passed through a solution for 193 sec ? Given F = 96500 C. \(N_0\) = 6.002 × \(10^{23}\) \(mol^{-1}\).
State Raoult’s law for a solution containing nonvolatile solute. What type of deviation from Raoult’s law is shown by a solution of chloroform and acetone and why?
The conductivity of metals decreases while that of electrolytes increases with increase in temperature. Why?
When chromite ore FeCr₂O₄ is fused with NaOH in presence of air, a yellow coloured compound
(A) is obtained which on acidification with dilute sulphuric acid gives a compound (B). Compound (B) on reaction with KCl forms a orange coloured crystalline compound (C).
(i) Write the formulae of the compounds (A), (B) and (C).
(ii) Write one use of compound (C).
State Raoult’s law. How is it formulated for solutions of non-volatile solutes ?
The conductivity of 0.20 M solution of KCl at 298 K is 0.025 Scm⁻¹. Calculate its molar conductivity.
What are colligative properties? Write the colligative property which is used to find the molecular mass of macromolecules.