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Class 10 Class 12
Analysis shows that nickel oxide has formula Ni 0.98 O1.00 What fractions of Nickel exist as Ni2+ and Ni3+ ions?

Formula is Ni0.98O1.00
So the ration of Ni : O = 98:100
So if there are 100 atoms of oxygen then 98 atoms of Ni,

Let number of atoms of Ni+2 = x
Then number of atoms of Ni+3 = 98–x
Charge on Ni = charge on O
So that oxygen has charge –2
3(98–x) + 2x = 2 (100)
294 –3x +2x = 200
–x = – 94
x = 94

Percentage of Ni+2 = (atom of Ni+2/total number of atoms of Ni)100
=100(94/98)x100
= 96%

Percentage of Ni+3
=100 – Ni+2
=100 – 96
= 4 %

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Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show clevage property?

Refractive index of a solid which have the same value along all directions are isotropic in nature. It would not show cleavage property.
1055 Views

Why do solids have a definite volume?

A solid have a definite volume because the inter molecular distance  between its molecules are fixed.
1439 Views

Why is glass considred a super-cooled liquid?

Glass is amorphous solids and  have a tendency to flow, though very slowly. Therefore, these are called pseudo solids or super cooled liquids .
1368 Views

Why are solids rigid?

Solids are rigid because the internuclear distance between the  molecules of a solid are very less and closely packed and their positions are fixed due to the strong forces of attraction between them.
2488 Views

Classify the following as amorphous or crystalline solids: Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.

Amorphous solids: Polyurethane, teflon, cellophane, polyvinyal chloride, fibre glass.
Crystalline solids: naphthlene, benzoic acid, potassium nitrate, copper.
1237 Views