The mass of carbon anode consumed (giving only carbondioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (Atomic mass Al= 27)
180 kg
270 kg
540 kg
90 kg
The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is
one-fifth
five
one
two
A reaction occurs spontaneously if
TS < H and both H and S are +ve
TS > H and both H and S are +ve
TS = H and both H and S are +ve
TS > H and H is +ve and S is - ve
The correct sequence of increasing covalent character is represented by
LiCl < NaCl < BeCl2
BeCl2 < NaCl < LiCl
NaCl < LiCl < BeCl2
BeCl2 < LiCl < NaCl
Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?
Exothermic and decreasing disorder
Endothermic and increasing disorder
Exothermic and increasing disorder
Endothermic and decreasing disorder
Which of the following is the electron deficient molecule?
B2H6
C2H6
PH3
SiH4
A.
B2H6
B2H6 is electron deficient molecule because boron atom has three half filled orbitals in excited state. The structure of B2H6 is represented as follows :
In it two electrons of a B - H bond are involved in formation of three centre bond, these bonds are represented as dotted lines.
A nuclide of an alkaline earth metal undergoes radioactive decay by emission of three -particles in succession. The group of the periodic table to which the resulting daughter element would belong to
Group 14
Group 16
Group 4
Group 6
The absolute enthalpy of neutralisation of the reaction
MgO(s) + 2HCl(aq) MgCl2(aq) + H2O(l)
will be
less than - 57.33 kJ mol-1
- 57.33 kJ mol-1
greater than-- 57.33 kJ mol-1
57.33 kJ mol-1
Equilibrium constants K1 and K2 for the following equilibria
NO (g) + NO2(g) and
2NO2(g) 2NO (g) + O2(g)
are related as