Which stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
(A) Frenkel defect
Which of the following Defects is also known as dislocation defect?
(A) Frenkel defect
(B) Schottky defect
(C) Non-stoichiometric defect
(D) Simple interstitial defect
The lattice site in a pure crystal cannot be occupied by __________.
(A) Molecule
(B) Ion
(C) Electron
(D) Atom
The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12
Graphite cannot be classified as __________.
(A) Conducting solid
(B) Network solid
(C) Covalent solid
(D) Ionic solid
Which of the following is an amorphous solid?
(A) Graphite (G)
(B) Quartz glass (SiO2)
(C) Chrome alum
(D) Silicon carbide (SiC)
What is the coordination number in a square close packed structure in two dimensions?
(A) 2
(B) 3
(C) 4
(D) 6
Which of the following conditions favours the existence of a substance in the solid state?
(A) High temperature
(B) Low temperature
(C) High thermal energy
(D) Weak cohesive forces
Limiting molar conductivity of NH4OH is equal to -:
a. Λᵒₘ(NH₄Cl) + Λᵒₘ(NaCl) + Λᵒₘ(NaOH)
b. Λᵒₘ(NaOH) + Λᵒₘ(NaCl) - Λᵒₘ(NH₄Cl)
c. Λᵒₘ(NaOH) - Λᵒₘ(NH₄Cl) - Λᵒₘ(HCl)
d. Λᵒₘ(NH₄Cl) + Λᵒₘ(NaOH) - Λᵒₘ(NaCl)
Which of the following conditions favours the existence of a substance in the solid state?
(A) High temperature
(B) Low temperature
(C) High thermal energy
(D) Weak cohesive forces
Which is incorrect statement.
a) Oxygen is the most abundant of all the elements on earth
b) Organic materials such as eggs, proteins, garlic, onion, mustard, hair and wool contain sulphur
c) Selenium and tellurium are found as metal selenides and tellurides in sulphide ores
d) Livermorium is a natural radioactive element
Aryl halides can not be prepared by the reaction of arylalcohols with \(PCl_3\), \(PCl_5\) or \(SOCl_2\) because :
(a) phenols are highly stable compounds.
(b) carbon-oxygen bond in phenols has a partial doublebond character.
(c) carbon-oxygen bond is highly polar
(d) all of these
The potential of a hydrogen electrode at pH = 10 is
a. 0.591 V
b. 0.00 V
c. – 0.591 V
d. -0.059 V
What is the coordination number in a square close packed structure in two dimensions?
(A) 2
(B) 3
(C) 4
(D) 6
The reaction R-Br + NaCN → R – CN + NaBr is an example of –
(a) Elimination Reaction.
(b) Nucleophilic Substitution.
(c) Electrophilic Substitution.
(d) Oxidation Reduction.