Explanation
All the given statements are correct
Germanium (like silicon ) is an intrinsic semiconductor
In Born –Haber cycle.electron affinity of the non-metal is most difficult to measure
The three-fold axes of symmetry in ccp are 4.
With increase of pressure, the boiling point increases.
Crystals show good cleavage because their constituent particles are arranged in planes
Both gases and liquids posses fluidity and hence viscosity. Molecules in the solid state do not have translational motion
When cation shifts from lattice to interstitial site, the defect is called Frenkel defect
Velocity and hence the K.E is maximum in the gaseous state.
In fluorite structure, co-ord. no. of Ca2+ = 8.
Ge belongs to Group 14 and In to Group 13. Hence on doping p – type semiconductor is obtained
Liquid crystals on heating first become turbid and then clear.
The existence of a substance in more than one solid modifications is known as polymorphism
A substance exists as a liquid above its m.pt and below its b.pt.
In a covalent solid, the units occupying the lattice points are atoms
When electrons are trapped in anion vacancies, these are called F– centres.
Yellow colour on heating NaCl in presence of Na is due to presence of electrons in anion vacancies (F- centres).
Energised electrons flow from hot end to cold end in a metal rod.
Pentavalent impurity mixed in germanium gives n – type semiconductor
ABAB…type is hcp which has 26% empty space.
H2O is polar. Hence it has higher critical temperature
In hcp, co-ordination number is 12
For BCC,packing fraction = 0.68
For octahedral arrangement (co-ordination no. = 6), radius ratio is in the range 0.414 – 0.732.
HCP has 12 nearest neighbours.
Surface tension of water decreases with increase in temperature
Co-ordination of Na+ in NaCl is 6.
With increase in temperature, viscosity of liquid decreases because the average kinetic energy of the molecules increases.
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