Explain why :
(i) E° for Mn³⁺/Mn²⁺ couple is more positive than that for Fe³⁺/Fe²⁺. (At. Nos. Mn = 25, Fe = 26).
(ii) Ce³⁺ can be easily oxidized to Ce⁴⁺. (At. No.Ce = 58).
(i) E° for Mn³⁺/Mn²⁺ couple is more positive than that for Fe³⁺/Fe²⁺. (At. Nos. Mn = 25, Fe = 26).
(ii) Ce³⁺ can be easily oxidized to Ce⁴⁺. (At. No.Ce = 58).
(i) Stable half-filled 3d³ configuration of Mn²⁺ results in high 3rd ionisation enthalpy of Mn. While in case of Fe²⁺, configuration is 3d⁶. Hence, it can easily loose one electron to give stable configuration 3d⁵.
(ii) Ce³⁺, ions having the configuration 4f¹5d⁰6d⁰ can easily lose electron to acquire the configuration 4f⁰5d⁰6s⁰ and form Ce⁴⁺ ion.
(ii) Ce³⁺, ions having the configuration 4f¹5d⁰6d⁰ can easily lose electron to acquire the configuration 4f⁰5d⁰6s⁰ and form Ce⁴⁺ ion.
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.
When Cu²⁺ ion is treated with KI, a white precipitate is formed. Explain the reaction with the help of chemical equation.
Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with (i) an iodide (ii) H₂S.
Metallic radii of some transition elements are given below. Which of these elements will have highest density?
Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group number.
Complete and balance the following chemical equations:
(a) Fe²⁺ + MnO₄⁻ + H⁺ →
(b) MnO₄⁻ + H₂O + I⁻ →
(i) Write the colligative property which is used to find the molecular mass of macromolecules.
(ii) In non-ideal solution, what type of deviation shows the formation of minimum boiling azeotropes?
(i) State the law which helps to determine the limiting molar conductivity of weak electrolyte.
(ii) Calculate limiting molar conductivity of CaSO₄ (limiting molar conductivity of calcium and sulphate ions are 119.0 and 160.0 Scm² mol⁻¹ respectively)
(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 ?
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..
Calculate the molality of ethanol solution in which the mole fraction of water is 0.88.
The partial pressure of ethane over a saturated solution containing 6.56 × 10⁻² g of ethane is 1 bar. If the solution were to contain 5.0 × 10⁻² g of ethane, then what will be the partial pressure of the gas ?
The conductivity of metals decreases while that of electrolytes increases with increase in temperature. Why?