19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
In a face centred cubic lattice, atom A occupies the corner positions and atom B occupies the face centre positions. If one atom of B is missing from one of the face centred points, the formula of the compound is
Which type of 'defect' has the presence of cations in the interstitial sites ?
Assertion : Glass is an amorphous solid. Reason : In glass, there is only short range order.
Assertion : The window glass of the old buildings is thick at bottom. Reason : Glass is a supercooled liquid of high viscosity and has the property to flow.
Assertion : Crystalline solids are anisotropic. Reason : The constituent particles are very closely packed.
Assertion : Covalent crystals have a higher melting point. Reason : Covalent bonds are stronger than ionic bonds.
Assertion : Graphite is an example of tetragonal crystal system. Reason : For a tetragonal system, a = b c, α = β = γ = 90º.
Assertion : If density of CsCl (cubic structure) is 3.99 g/cm3, the distance between Cs+ and Cl- ions will be 357 pm [atomic mass of Cs = 133]. Reason : CsCl has bcc lattice.
Assertion : Packing in body centered cubic (bcc) structure is more efficient than in cubic closed packed (ccp) structure. Reason : 74% of the total space is occupied by the atoms in fcc structure while only 68% of the…
Assertion : If three elements A, B and C crystallize in a cubic solid lattice with A atoms at the corners, B atoms at the cube centre and C atoms at the centre of the faces of the cube, then the formula of the compoun…
Formula of nickel oxide with metal deficiency defect in its crystal is Ni0.98O. The crystal contains Ni2+ and Ni3+. ions. The fraction of nickel existing as Ni2+ ions in the crystal is (NEET (Odisha) 2019)
The tetrahedral voids present in 0.5 mole of hcp crystal structure are (AIIMS 2019) (a) 3.6 10 x (b) 9 10 x (c) 3.6 10 x (d) 6.02 10 x
Which type of defect present in NaCl ? (JIPMER 2019)
Ag crystallises as fcc. If radius of Ag is 144 pm then its density will be (a)10 g cm–3
In a crystalline solid, having formula XY2O4, oxide ions are arranged in cubic close packed lattice while, cations X are present in tetrahedral voids and cations Y are present in octahedral voids. The percentage of te…
The correct option for the number of body centred cubic unit cells in all 14 types of Bravais lattice unit cells is: [NEET 2021]
Assertion : Co-ordination number of rock salt is 8. Reason : Limiting radius ratio for rock salt is between 0.414 and 0.732.
Example of unit cell with crystallographic dimensions , 90º, 90º a b c is
Assertion : In caesium chloride structure, Cl- ions are at the corners of a primitive cubic array and Cs+ ions fits into big central empty region in each Cl- array. Reason : The radius ratio r Cs r Cl is greater tha…
A metallic element has a cubic lattice. Each edge of the unit cell is 2 Å. The density of the metal is 2.5 g cm–3 . The unit cells in 200 g of the metal are
Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are [NEET 2021]
Assertion : Unlike Schottky defects, Frenkel defects don’t change the density of solids. Reason : These defects are basically point defects.
Assertion : In Schottky defects, electrical neutrality is maintained. Reason : Equal number of cation and anion vacancies are present.
Solid SO2 and NH3 are the examples of which of the following types of solids? (CBSE 2018)
Which of the following is an example of network solid? (AIIMS 2018) (a) SO Solid (b) 2I