Number of three-centre two-electron (3e-2e) bonds present in diborane is:
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The lattice energy of LiF calculated from Born-Lande equation – 1000 kJ mol–1. Assume that for both LiF and MgO the Madelung constants, interionic distances and Born exponents have the same value. The lattice energy of MgO in kJ mol–1 is:
The hydrogen-oxygen fuel cells have electrolyte solution of 2.5% __________
Number of moles of ions produced by complete dissociation of one mole of Mohr ’s salt in water is
The tetrachloro complexes of Ni(II) and Pd(II) respectively, are (atomic numbers of Ni and Pd are 28 and 46 respectively)
The total number of steps involved and number of beta particles emitted in the spontaneous decay of Pb respectively, are
A filter paper moistioned with ammonical sodium nitroprusside solution turns violet on contact with a drop of alkaline Na2S solution. The violet colour is due to the formation of
The species/compounds that are aromatic among the following are
The major product obtained in the reaction below is
The rates of acetolysis for the following norbornyl derivatives are in the order
The Haworth projection for a-anomer of D-glucose is
The complementary DNA sequence of the given DNA 5’-G-A-A-T-T-C-3’ is:
The order of nucleophilicity of the following anions in a SN2 reaction is:
The pair of conformation that has maximum energy difference is:
The major mono-sulfonation product of α-tetralone is
Electrophilic nitrations of the following compounds follow the trend
The compounds those would not respond to tests of both nitrogen and sulfur with sodium fusion extracts are
For the equilibrium , the equilibrium constant, KP is expressed as
The average speed of H2, N2 and O2 gas molecules is in the order
The molality of (NH4)2SO4 solution that has the same ionic strength as 1 mol kg–1 solution of KCl is
The standard enthalpy of formation ( Δf U0300 ) at 1 bar and 300 K for the formation of CF2ClCF2Cl(g) from its constituent elements in the standard state is -900 kJ mol-1. Given R = 8.3 J K-1 mol-1, the standard internal energy of formation ( Δf U0300 ) at the same pressure and temperature is
The percent transmittance of a solution having absorbance (optical density) 1.0 is
A concentration cell with two hydro gen electro des at t wo differnet pressures is depicted as
The potential (Ecell) of the cell is
An aqueous solution containing 1 g L–1 of a polymer exerts osmotic pressure of 4 torr at 300 K.Given R = 0.082 L atm, the molar mass (g mol–1) of the polymer is