CBSE 12th Standard Chemistry Subject The d- and f- Block Elements HOT Questions Fill Up Questions 2021
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CBSE 12th Standard Chemistry Subject The d- and f- Block Elements HOT Questions Fill Up Questions 2021
12th Standard CBSE
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Reg.No. :
Chemistry
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K2PtCI6 is a well known compound whereas corresponding Ni Compound is not known. State a reason for it.
(a)This is because Pt4+ is more stable than Ni4+ as the sum of four ionization enthalpies of Pt is less than that of Ni.
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Explain why, Zn (II) salts are white while Mn (VII) are deep purple in colour?
(a)due to charge transfer between O2- ion to Mn7+.
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KMnO4 is used in acidic medium quite frequently than in its aqueous or alkali for oxidizing purpose. Why?
(a)In acidic medium MnO4 - involves the addition of 5e- or Eo = +1.52v
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Give reasons:
i) Zr and Hf have identical sizes
ii) In the titration of FeSO4 with KMnO4 in the acidic medium dil. H2SO4 is used instead of dil HCl.(a)i) Due to lanthanoid contraction
ii) dil.HCl is reducing agent and liberates chlorine on reacting with KMnO4 soln.
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CBSE 12th Standard Chemistry Subject The d- and f- Block Elements HOT Questions Fill Up Questions 2021 Answer Keys
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This is because Pt4+ is more stable than Ni4+ as the sum of four ionization enthalpies of Pt is less than that of Ni.
This is because Pt4+ is more stable than Ni4+ as the sum of four ionization enthalpies of Pt is less than that of Ni.
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due to charge transfer between O2- ion to Mn7+.
due to charge transfer between O2- ion to Mn7+.
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In acidic medium MnO4 - involves the addition of 5e- or Eo = +1.52v
In acidic medium MnO4 - involves the addition of 5e- or Eo = +1.52v
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i) Due to lanthanoid contraction
ii) dil. HCl is reducing agent and liberates chlorine on reacting with KMnO4 soln.i) Due to lanthanoid contraction
ii) dil. HCl is reducing agent and liberates chlorine on reacting with KMnO4 soln.
