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
(A) Frenkel defect
(B) Schottky defect
(C) Non-stoichiometric defect
(D) Simple interstitial defect
(A) Frenkel defect
Which stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
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
Graphite cannot be classified as __________.
(A) Conducting solid
(B) Network solid
(C) Covalent solid
(D) Ionic solid
The lattice site in a pure crystal cannot be occupied by __________.
(A) Molecule
(B) Ion
(C) Electron
(D) Atom
What is the coordination number in a square close packed structure in two dimensions?
(A) 2
(B) 3
(C) 4
(D) 6
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
RNA and DNA are chiral molecules. Their chirality is due to :
(a) Chiral bases
(b) Chiral phosphate ester units
(c) D-sugar component
(d) L-sugar component.
Each polypeptide in protein has amino acids linked with each other in a specific sequence. This sequence of amino acids is said to be-
(a) primary structure of proteins.
(b) secondary structure of proteins.
(c) tertiary structure of proteins.
(d) quaternary structure of proteins.
1-Phenylethanol can be prepared by the reaction of benzaldehyde with
(a) methyl bromide.
(b) ethyl iodide and magnesium.
(c) methyl iodide and magnesium.
(d) methyl bromide and aluminium bromide.
Highest oxidation state of manganese in fluoride is +4 (MnF₄) but highest oxidation state in oxides is +7 (Mn₂O₇) because
(a) fluorine is more electronegative than oxygen.
(b) fluorine does not possess d-orbitals.
(c) fluorine stabilises lower oxidation state.
(d) in covalent compounds fluorine can formsingle bond only while oxygen forms double bond.
Molecules whose mirror image is non-superimposable over them are known as chiral. Which of the following molecules is chiral in nature?
(a) 2-Bromobutane.
(b)1-Bromobutane.
(c) 2-Bromopropane.
(d) 2-Bromopropan-2-ol.
Which of the following statements is not true about amorphous solids?
(A) On heating they may become crystalline at certain temperature.
(B) They may become crystalline on keeping for long time.
(C) Amorphous solids can be moulded by heating.
(D) They are anisotropic in nature.