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प्रश्न
What is meant by ‘disproportionation’?
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उत्तर
The oxidation and reduction of a substance at the same time as a result of a chemical reaction is called disproportionation.
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संबंधित प्रश्न
Account for the following:
Cr2+ is a strong reducing agent.
Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
Calculate the ‘spin only’ magnetic moment of \[\ce{M^{2+}_{ (aq)}}\] ion (Z = 27).
How would you account for the following:
The d1 configuration is very unstable in ions.
What are alloys?
Give reasons Iron has the higher enthalpy of atomization than that of copper.
How is potassium dichromate prepared from chrome iron ore?
Explain why transition metals and their compounds act as a catalyst.
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
Electronic configuration of Mn2+ is ____________.
Read the passage given below and answer the following question:
The transition metals when exposed to oxygen at low and intermediate temperatures form thin, protective oxide films of up to some thousands of Angstroms in thickness. Transition metal oxides lie between the extremes of ionic and covalent binary compounds formed by elements from the left or right side of the periodic table. They range from metallic to semiconducting and deviate by both large and small degrees from stoichiometry. Since electron bonding levels are involved, the cations exist in various valence states and hence give rise to a large number of oxides. The crystal structures are often classified by considering a cubic or hexagonal close-packed lattice of one set of ions with the other set of ions filling the octahedral or tetrahedral interstices. The actual oxide structures, however, generally show departures from such regular arrays due in part to distortions caused by packing of ions of different size and to ligand field effects. These distortions depend not only on the number of d-electrons but also on the valence and the position of the transition metal in a period or group.
In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
Assertion: Transition metals form protective oxide films.
Reason: Oxides of transition metals are always stoichiometric.
Transition elements show high melting points. Why?
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d orbital but reverse happens during the ionisation of the atom. Explain why?
Assertion: \[\ce{Cu^2+}\] iodide is not known.
Reason: \[\ce{Cu^2+}\] oxidises \[\ce{I^-}\] to iodine.
A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese are formed. Compound (C) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C) with conc. \[\ce{H2SO4}\] and \[\ce{NaCl}\], chlorine gas is liberated and a compound (D) of manganese along with other products is formed. Identify compounds A to D and also explain the reactions involved.
A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?
Which of the following transition metal is not coloured?
The value of Δ0 for \[\ce{RhCl^{3-}6}\] is 243 KJ/mol which wavelength of light will promote an electron from. The colour of the complex is ______.
A coordination compound has the formula \[\ce{CoCl3.4NH3}\]. It precipitates silver ions as AgCl and its molar conductance corresponds to a total of two ions.
Based on this information, answer the following question:
- Deduce the structural formula of the complex compound.
- Write the IUPAC name of the complex compound.
- Draw the geometrical isomers of the complex compound.
