Last seen: Jan 13, 2022
(c) Assertion is correct but Reason is wrong. Explanation: All edge centres and body centre represent octahedral void. Total number of octahedr...
(b) Assertion and Reason both are correct statements but Reason is not the correct explanation for Assertion. Explanation: Diamond is bad conducto...
(a) Assertion and Reason both are correct statements and Reason is the correct explanation for Assertion. Explanation: In simple cubic unit cell, ...
An amorphous solid on heating at some temperature may become crystalline. Slow heating and cooling over a long period makes an amorphous solid acquire...
In ccp, no. of atoms per unit cell = 4 Thus, of tetrahedral voids = 2 x No. of atoms in ccp = 2 x 4 = 8 Only one-third of tetrahedral voids are oc...
The energy gap between valence band and conduction band is small. At room temperature, they do not conduct electricity but when temperature is raised ...
When ZnO is heated, it splits up to give Zn2+, electrons and colour because of the following reasons: The excess Zn ions thus formed get entrapped ...
Iron oxide (FeO) has rock salt structure. In this case, O2 ions adopt on sites and Fe2+ ions should occupy non- stoichiometric. This is the ideal ar...
The yellow colour of sodium chloride crystals is due to metal excess defect. In this defect, the unpaired electrons get trapped in anion vacancies. Th...
Crystals have long range in the arrangement of particles but usually the crystals are not perfect this is because when crystallisation occurs at a fas...
The intermuclear distance between the constituent particles (atoms, molecules or ions) in solids are very less. On bringing them further closer, there...
The liquids and gases have a property to flow i.e., the molecules of liquids and gases can easily move fast and tumble over one another freely. Becaus...
(b, d) Explanation: Vacancy and Schottky defect which lead to decrease the density both are the types of a stoichiometric defect. In case of Frenk...
(a, b) Explanation: In Frenkel defect, dislocation of cations takes place and there is no change in stoichiometry of the crystal.
(a, d) Explanation: In hep and fee arrangement, octahedral voids are formed. In fee, the octahedral voids are observed at edge and centre of cube ...
(a, b, c) Explanation: SiC, AIN and diamond are examples of network solid as they have three dimensional structure while, I2 is a molecular solid,...
(a, c) Explanation: Quartz glass is an amorphous solid so it has not definite heat of fusion. This is due to short range order of molecule while q...
(a, d) Explanation: Ferrimagnetic substances lose ferrimagnetism on heating and become paramagnetic. In ferromagnetic substance, domains are align...
(a, c) Explanation: Amorphous solid has short range order which has a tendency to flow very slowly. Hence, it is also known as pseudo solids or su...
(c, d) Explanation: NaCl has fee arrangement of CF ions. Thus, Number of CF ions in packing per unit cell = 4 Number of tetrahedral voids = ...