The correct order of the packing efficiency in different types of unit cells is ________.
(A) fcc < bcc < simple cubic
(B) fcc > bcc > simple cubic
(C) fcc < bcc > simple cubic
(D) bcc < fcc = simple cubic
(A) fcc < bcc < simple cubic
(B) fcc > bcc > simple cubic
(C) fcc < bcc > simple cubic
(D) bcc < fcc = simple cubic
(B) fcc > bcc > simple cubic
The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12
The lattice site in a pure crystal cannot be occupied by __________.
(A) Molecule
(B) Ion
(C) Electron
(D) Atom
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)
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 of the following Defects is also known as dislocation defect?
(A) Frenkel defect
(B) Schottky defect
(C) Non-stoichiometric defect
(D) Simple interstitial defect
Which stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
When KMnO₄ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because
(a) CO₂ is formed as the product.
(b) The reaction is exothermic.
(c) MnO₄⁻ catalyses the reaction.
(d) Mn²⁺ acts as an auto-catalyst.
When mercuric iodide is added to the aqueous solution of potassium iodide, the:
(a) Freezing point is raised
(b) Freezing point does not change
(c) Freezing point is lowered
(d) Boiling point does not change
Assertion: Glycine must be taken through diet.
Reason: It is essential amino acid.
A. Assertion and reason both are correct statements and reason is correct explanation for assertion.
B. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
C. Assertion is correct statement but reason is wrong statement.
D. Assertion is wrong statement but reason is correct statement.
Solid A is very hard electrical insulator in solid as well as in molten state and melts at an extremely high temperature. What type of solid is it?
(A) Ionic solid
(B) Molecular solid
(C) Covalent solid
(D) Metallic solid
The decreasing order of boiling point of the following alcohols is
(a) 3-methylbuan-2-ol > 2-methylbutan-2-ol > pentan-1-ol.
(b) Pentan-1-ol > 3-methylbutan-2-ol > 2-methylbutan-2-ol.
(c) 2-methylbutan-2-ol > 3-methylbutan-2-ol > pentan-1-ol.
(d) 2-methylbutan-2-ol > pental-1-ol > 3-methylbutan-2-ol.
The electronic configuration of Cu(II) is 3d⁹ whereas that of Cu(I) is 3d¹⁰. Which of the following is correct?
(a) Cu(II) is more stable
(b) Cu(II) is less stable
(c) Cu(I) and Cu(II) are equally stable
(d) Stability of Cu(I) and Cu(II) depends on nature of copper salts
Benzene reacts with \(CH_3\)Cl in the presence of anhydrous \(AlCl_3\) to form:
(a) chlorobenzene
(b) benzylchloride
(c) xylene
(d) toluene