The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12
(A) 6
(B) 8
(C) 10
(D) 12
(B) 8
What is the coordination number in a square close packed structure in two dimensions?
(A) 2
(B) 3
(C) 4
(D) 6
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 stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
Chlorine water on standing loses its yellow colour due to the formation of
a) Cl and HOCl.
b) HCl and HOCl.
c) HOCl and \(HOCl_2\).
d) HCl and \(HOCl_2\).
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
Which is the correct statement?
a) valence shell electronic configuration of group 16 elements is \(ns^1\)\(np^4\).
b) the elements of group 16 have lower ionisation enthalpy values compared to those of Group 15 in the corresponding periods.
c) Oxygen atom has more negative electron gain enthalpy than sulphur.
d) oxygen has the highest electronegativity value amongst the elements.
The lowest boiling point of helium is due to its
a) Inertness
b) Gaseous nature
c) Weak van der Waals force between atoms
d) electronic configuration
Order of esterification of alcohols are
(a) 3° > 1° > 2°.
(b) 2°> 3° > 1°.
(c) 1 ° > 2° > 3°.
(d) None of these.
The order of reactivity of the following alcohols with halogen acids is
One mole of ethyl acetate on treatment with an excess of \(LiAlH_4\) in dry ether and subsequent acidification produces
(a) 1 mole acetic acid + 1 mole ethyl alcohol.
(b) 1 mole ethyl alcohol + 1 mole methyl alcohol.
(c) 2 moles of ethyl alcohol.
(d) 1 mole of 2-butanol.