Multiple Choice Questionsexcess of PCl5 reacts with concentrated H2SO4 giving
chlorosulphuric acid
sulphurous acid
sulphury chloride
thionyl chloride
Which one of the following shows highest magnetic moment?
Fe2+
Co2+
Cr3+
Ni2+
A.
Fe2+
The paramagnetism or magnetic moment produced due to spin of electrons or unpaired electrons is expressed in terms of Bohr magneton (BM) or μB and given by
Magnetic moment (μ) =√[n(n+2)]BM
where n is the number of unpaired electron, in species. Thus, greater is the number of unpaired electron is an ion greater is its paramagnetic nature.
| Ion | electronic configuration | No. of unpaired e- s |
| Cr3+ | d3 | 3 |
| Fe2+ | d6 | 4 |
| Co2+ | d7 | 3 |
| Ni2+ | d8 | 2 |
As Fe2+ ion has maximum number of unpaired electrons, thus it has highest magnetic moment.
The emf of a galvanic cell constituted with the electrode Zn2+|Zn (-0.76V) and Fe2+|Fe (-0.41V) is
-0.35V
+ 1.17V
+0.35V
-1.17V
Which of the following is not a colligative property?
Elevation in boiling point
Depression in freezing point
Osmotic pressure
Lowering of vapour pressure
3 g of urea is dissolved in 45 g of H2O. The relative lowering in vapour pressure is
0.05
0.04
0.02
0.01
Metallic lustre is due to
high density of metals
high polish on the surface of metals
reflection of light by mobile electrons
chemical inertness of metals
Which of the following aqueous solution will exhibit highest boiling point?
0.01M urea
0.01 M KNO3
0.01M Na2SO4
0.015M C6H12O6
Oils are liquids at room temperature since they contain higher percentage of
oleates
palmitates
stearates
myristates
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