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.
(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.
(D) They are anisotropic in nature.
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 is true about the value of refractive index of quartz glass?
(A) Same in all directions
(B) Different in different directions
(C) Cannot be measured
(D) Always zero
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 of the following is an amorphous solid?
(A) Graphite (G)
(B) Quartz glass (SiO2)
(C) Chrome alum
(D) Silicon carbide (SiC)
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
Which stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
Which is the most reactive towards SN1 reaction –
a) \(C_6\)\(H_5\)\(CH_2\)Cl.
b) \(C_6\)\(H_5\)CH(\(C_6\)\(H_5\))Br.
c) \(C_6\)\(H_5\)CH(\(CH_3\))Br.
d) \(C_6\)\(H_5\)C(\(CH_3\))(\(C_6\)\(H_5\))Br.
Stability of hydrides of group 16 elements
a) increases down the group
b) decreases down the group
c) all hydrides are equally stable
d) none of the above
Acid catalysed dehydration of t-butanol is faster than that of n-butanol because
(a) tertiary carbocation is more stable than primary carbocation.
(b) primary carbocation is more stable than tertiary carbocation.
(c) t-butanol has a higher boiling point.
(d) rearrangement takes place during dehydration of t- butanol.
Which of the following alcohols gives 2-butenc on dehydration by conc.\(H_2\)\(SO_4\)?
(a) 2-methyl propene-2-ol.
(b) 2-methyl 1 -propanol.
(c) Butane-2-ol.
(d) Butane 1-ol.
The order of reactivity of the following alcohols with halogen acids is
The sharp melting point of crystalline solids is due to ___________.
(A) a regular arrangement of constituent particles observed over a short distance in the crystal lattice.
(B) a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
(C) same arrangement of constituent particles in different directions.
(D) different arrangements of constituent particles in different directions.
Equimolar solutions in the same solvent have-
(a) Same boiling point but different freezing point
(b) Same freezing point, but different boiling point
(c) Same boiling and same freezing point
(d) Different boiling and different freezing points