© examsnet.com
Question : 29
Total: 30
(a) Complete the following equations:
(i)Cr 2 O 7 2 − + 2 OH − →
(ii)MnO 4 − + 4 H + + 3 e − →
(b) Account for the following:
(i)Zn
(ii) Transition metals form a larger number of complexes.
(iii) TheE Mn 3 + ∕ Mn 2 + Cr 3 + ∕ Cr 2 +
OR
(i) With reference to structural variability and chemical reactivity, write the difference between lanthanoids and actionoids.
(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iii) Complete the following equation:
MnO 4 − + 8 H + + 5 e − →
(vi) Out ofMn 3 + Cr 3 + Mn = 25 Cr = 24 )
(i)
(ii)
(b) Account for the following:
(i)
(ii) Transition metals form a larger number of complexes.
(iii) The
OR
(i) With reference to structural variability and chemical reactivity, write the difference between lanthanoids and actionoids.
(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iii) Complete the following equation:
(vi) Out of
Solution:
(a) (i) Cr 2 O 7 2 − + 2 OH − ─ ─ ─ ─ ▸ 2 CrO 4 2 − + H 2 O
(ii)MnO 4 − + 4 H + + 3 e − ─ ─ ─ ─ ▸ MnO 2 + 2 H 2 O
(b) (i) The transition metals are compounds that form at least 1 stable ion, where the compound has an incompleted Zn 3 d
(ii) Transition metal shows a variable oxidation state, so they form a large number of complexes.
(iii) It is becauseMn 2 + Mn 3 + 3 d 5 Cr 3 + ( t 2 g ) ( 3 d 5 ) Cr 2 +
OR
(i) The differences between lanthanoids and actinoids with respect to their structural variability and chemical reactivity are as follows:
(a) Actinoids are radioactive, while lanthanoids are not radioactive.
(b) The ionisation enthalpies of the early actinoids are lower than those of the early lanthanoids. Actinoids show the oxidation state from +3 (most common) to +7 , while lanthanoids show the oxidation state from +3 up to +7 .
(c) Actinoids are more reactive and have more complex magnetic properties than lanthanoids.
(ii) Cerium is a lanthanide element that is known to exhibit the oxidation state of 4
(iii) The complete equation is as follows:
MnO 4 − + 8 H + + 5 e − ─ ─ ─ ─ ▸ Mn 2 + + 4 H 2 O
(iv)Mn 2 + Cr 3 +
(ii)
(b) (i) The transition metals are compounds that form at least 1 stable ion, where the compound has an incomplete
(ii) Transition metal shows a variable oxidation state, so they form a large number of complexes.
(iii) It is because
OR
(i) The differences between lanthanoids and actinoids with respect to their structural variability and chemical reactivity are as follows:
(a) Actinoids are radioactive, while lanthanoids are not radioactive.
(b) The ionisation enthalpies of the early actinoids are lower than those of the early lanthanoids. Actinoids show the oxidation state from +3 (most common) to +7 , while lanthanoids show the oxidation state from +3 up to +7 .
(c) Actinoids are more reactive and have more complex magnetic properties than lanthanoids.
(ii) Cerium is a lanthanide element that is known to exhibit the oxidation state of 4
(iii) The complete equation is as follows:
(iv)
© examsnet.com
Go to Question: