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प्रश्न
Define Anisotropy.
उत्तर
The ability of crystalline solids to change values of physical properties when measured in different directions is called anisotropy.
संबंधित प्रश्न
The major binding force in diamond is_______________ .
(a) Covalent bond
(b) Ionic bond
(c) Metallic bond
(d) Co-ordinate covalent bond
What is the covalency of nitrogen in N2O5?
Give an example each of a molecular solid and an ionic solid.
Solid A is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?
Classify the following molecular solids into different types:
- HCl
- CO2
- Solid ice
- SO2
Account for the following :
o-nitrophenol is more steam volatile than p-nitrophenol.
Answer the following in one or two sentences.
A solid is hard, brittle and electrically nonconductor. Its melt conducts electricity. What type of solid is it?
Answer the following in brief.
Distinguish between ionic solids and molecular solids
A compound is made up of two elements X and Y and crystallizes in bcc structure. Atoms of X are present at the corners of the cube. Atoms of Y are present at the centre of the cube. The formula of the compound is ______.
Sodium crystallizes in bcc structure. If the edge length of unit cell is 4.3 × 10-8 cm, the radius of Na atom is ______.
Graphite and diamond are ____________.
An ionic compound AxBy crystallizes in fcc type crystal structure with B ions at the centre of each face and A ion occupying corners of the cube. the correct formula of AxBy is
Assertion: monoclinic sulphur is an example of a monoclinic crystal system
Reason: for a monoclinic system, a ≠ b ≠ c and α = γ = 90°, β ≠ 90°
In calcium fluoride, having the flurite structure the coordination number of Ca2+ ion and F− Ion are ____________.
The ionic radii of A+ and B− are 0.98 × 10−10 m and 1.81 × 10−10 m. the coordination number of each ion in AB is
Define unit cell.
Give any three characteristics of ionic crystals.
Differentiate crystalline solids and amorphous solids.
Classify the following solid.
Diamond
Classify the following solid.
Iodine
Select the INCORRECT match:
____________ is an example of molecular crystal.
Dry ice is an example of ____________.
Fullerene is an example of ____________.
Brass is an example of ____________.
Solid X is a very hard electrical insulator in solid as well as in molten state. It melts at extremely high temperature. Solid X is a ____________.
Order of increasing melting points among H2O(s), C(s), CS2 and Sn is ____________.
What type of interaction hold the molecules together in a polar molecular solid?
London forces are present in ____________.
The compound, found in nature in gas phase but ionic in solid state is ____________.
Solid CH4 is ____________.
An example of a covalent crystalline solid is ____________.
Which of the following exists as covalent crystals in the solid state?
The major binding force of diamond, silicon and quartz is ____________.
Which one of the following forms a molecular solid when solidified?
Which of the following is a network solid?
Iodine molecules are held in the crystals lattice by ______.
Which of the following is not the characteristic of ionic solids?
NaCl type crystal (with coordination no. 6 : 6) can be converted into CsCl type crystal (with coordination no. 8 : 8) by applying ____________.
How many chloride ions are surrounding sodium ions in sodium chloride crystal?
Which of the following is not true about the ionic solids?
An excess of potassium ions makes KCl crystals appear violet or lilac in colour since:
(i) some of the anionic sites are occupied by an unpaired electron.
(ii) some of the anionic sites are occupied by a pair of electrons.
(iii) there are vacancies at some anionic sites.
(iv) F-centres are created which impart colour to the crystals.
Which of the following cannot be regarded as molecular solid?
(i) SiC (Silicon carbide)
(ii) AlN
(iii) Diamond
(iv) I2
Why are liquids and gases categorised as fluids?
A crystal with a ≠ b ≠ c and α = β = γ = 90° is
Who introduced the term covalent bond?
Calculate the angle at which first order reflection will occurs in an X-ray spectrometer when x ~ rays of wavelength \[\ce{1.54 \overset{\circ}{A}}\] are diffracted by the atoms of a crystal given that inter planer distance is \[\ce{0.04 \overset{\circ}{A}}\]
A reddish-pink substance on heating gives off a vapour which condenses on the sides of the test tube and the substance turns blue. If on cooling water is added to the residue it turns to original colour. The substance is ______.
Among the following which is the best description of water in the solid phase?
Mention the res of the following solid:
CO2
