19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Those substances which show permanent magnetism even in the absence of magnetic field are called
Electrons in a paramagnetic compound are
On the basis of their magnetic properties, substances can be classified into …A… categories. Here, A refers to
Identify the incorrect statement.
In NaCl lattice the radius ratio is Na Cl r r =
In a solid lattice the cation has left a lattice site and is located at an interstitial position, the lattice defect is
Which of the following has the highest value of energy gap?
Doping of silicon (Si) with boron (B) leads to
A metal crystallises into a lattice containing a sequence of layer as AB ABAB....... . What percentage of voids are left in the lattice?
Which kind of defect is shown by the given crystal?
The correct option for the number of body centred cubic unit cells in all 14 types of Bravais lattice unit cells is: [NEET 2021]
Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are [NEET 2021]
Which of the following defects are also called thermodynamic defects?
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)
Number of atoms in the unit cell of Na (bcc type crystal) and Mg (fcc type crystal) are, respectively
Niobium crystallises in body centred cubic structure. If density is 8.55 g cm-3, then the atomic radius of niobium is (atomic mass of niobium = 93u) (AllMS 2018)
An atom forms face centred cubic crystal with density d = 8.92g/mL and edge length a 3.6 10 cm x . The molecular mass of atom in amu is (JIPMER 2018)
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…
A solid has a structure in which W atoms are located at the corners of a cubic lattice. O atoms at the centre of edges and Na atom at centre of the cube. The formula for the compound is (AllMS 2018) (a) NaWO (b) NaWO …
Total volume of atoms present in a face centred cubic unit cell of a metal is (r = radius of atom) (a) r (b) r (c) r (d) r
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…
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.