Advertisements
Advertisements
प्रश्न
Assertion: Separation of \[\ce{Zr}\] and \[\ce{Hf}\] is difficult.
Reason: Because \[\ce{Zr}\] and \[\ce{Hf}\] lie in the same group of the periodic table.
पर्याय
Both assertion and reason are true, and reason is the correct explanation of the assertion.
Both assertion and reason are true but reason is not the correct explanation of assertion.
Assertion is not true but reason is true.
Both assertion and reason are false.
Advertisements
उत्तर
Both assertion and reason are true but reason is not the correct explanation of assertion.
Explanation:
Although \[\ce{Zr}\] and \[\ce{Hf}\] lie in same group but As an effect of lanthanide contraction, zirconium and hafnium have similar radius of 160 pm and 159 pm respectively. Due to this similarity in their size, they show similar physical and chemical properties. As a result, \[\ce{Zr}\] and \[\ce{Hf}\] are difficult to separate. Both the statements assertion and reason are correct but reason is not the correct explanation of assertion.
APPEARS IN
संबंधित प्रश्न
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Write the element which shows maximum number of oxidation states. Give reason.
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element shows only +3 oxidation state?
Which of the d-block elements may not be regarded as the transition elements?
In what way is the electronic configuration of the transition elements different from that of the non-transition elements?
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.
Explain why transition metals and their compounds act as a catalyst.
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: Crystal structure of oxides of transition metals often show defects.
Reason: Ligand field effect cause distortions in crystal structures.
Which of the following statements is not correct?
Why EΘ values for Mn, Ni and Zn are more negative than expected?
Out of \[\ce{Cu2Cl2}\] and \[\ce{CuCl2}\], which is more stable and why?
The halides of transition elements become more covalent with increasing oxidation state of the metal. Why?
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid, compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.
The spin magnetic moment of cobalt in the compound Hg [Co(SCN)4] is:-
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
The trend of which property is represented by the following graph?
In order to protect iron from corrosion, which one will you prefer as a sacrificial electrode, Ni or Zn? Why? (Given standard electrode potentials of Ni, Fe and Zn are -0.25 V, -0.44 V and -0.76 V respectively.)
Account for the following:
Zirconium (Zr) and Hafnium (Hf) are difficult to separate.
Decide which of the following atomic numbers are the atomic numbers of the inner transition elements:
29, 59, 74, 95, 102, 104
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Atomic sizes
