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CBSE chemistry

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Question
CBSEENCH12010258
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Zn2+ salts are white while Cu2+ salts are coloured. Why?

Solution

Element/Ion

Electronic Configuration

Zn

3d10 4s2

Zn2+

3d10

Cu

3d10 4s1

Cu2+

3d9


The colours of salts of transition metals are due to the d-d transition that depends on the presence of incompletely filled d-orbitals. Zn2+ has completely filled d-orbitals (3d10), while Cu2+ has incompletely filled d-orbitals (3d9); therefore, d-d transition is possible in Cu2+, which imparts colour to copper (II) salts.

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Question
CBSEENCH12010260
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How much charge is required for the reduction of 1 mol of Zn2+ to Zn?

Solution

Zn2+ + 2e- ---> Zn
Number of electrons involved = 2
Charge required for the reduction of Zn2+ = 2F
We know
1F = 96,487 C
Thus,
2F = 2 x 96487 = 1,92,974 C

Question
CBSEENCH12010261
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Write the dispersed phase and dispersion medium of butter.

Solution

In colloidal dispersion, one substance is dispersed as very fine particles in another substance called dispersion medium. In the case of dust, solid particles are dispersed in air as the dispersion medium.

Dispersed phase: Liquid
Dispersion medium: Solid

Question
CBSEENCH12010263
Wired Faculty App

Write the structures of the following molecules:
(i) H2SO3
(ii) XeOF4

Solution

 

Molecules

Structures

(i)

H2SO3

  

(ii)

XeOF4

 

Question
CBSEENCH12010264
Wired Faculty App

Write down the IUPAC name of the complex [Pt(en)2Cl2]2+. What type of isomerism is shown by this complex?

Solution

Complex: [Pt(en)2Cl2]2+
IUPAC name: Dichloridobis(ethane-1,2-diammine)platinum(IV) ion
Isomerism: Geometrical isomerism

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