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The D-And-f-Block Elements

Question
CBSEENCH12007287
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How does the acidified KMnO4 react with the following:
(a) Iron(II) solution, (b)SO32–, (c) Iodide (I–) ion, (d) oxalic acid, (e) NO2– (Nitrite ion).

Solution

a) Fe2+ ion (green) is converted to Fe3+ (yellow):

5Fe2+ + MnO4– + 8H+ ——> Mn2+ + 4H2O + 5Fe3+

b) Sulphurous acid or sulphite is oxidised to a sulphate or sulphuric acid:

5SO32– + 2MnO4– + 6H+ ——> 2Mn2+ + 3H2O + 5SO42–


c) Iodine is liberated from potassium iodide :

10I– + 2MnO4– + 16H+ ——> 2Mn2+ + 8H2O + 5I2


d) Oxalate ion or oxalic acid is oxidised at 333 K:

5C2O42– + 2MnO4– + 16H+ ——> 2Mn2+ + 8H2O + 10CO2


e) Nitrite is oxidised to nitrate:

5NO2– + 2MnO4– + 6H+ ——> 2Mn2+ + 5NO3– + 3H2O

Some More Questions From The d-And-f-Block Elements Chapter

Explain why Cu+ ion is not stable in aqueous solutions?

Actinoid contraction is greater from element to element than lanthanoid contraction. Why?

On what ground can you say that scandium (Z = 21) is a transition element but zinc (Z = 30) is not?

The outer electronic configuration of copper is 3d10 4s1, yet it is considered transition element. Why?

Why the melting points of transition elements are high?

Why Zn, Cd and Hg are not regarded as transition elements?

Name the first element of 3rd transition series.

Though copper, silver and gold have completely filled sets of d-orbitals yet they are considered as transition metals. Why?

Why are transition elements so named?

Why are transition elements known as d-block elements?

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