Multiple Choice QuestionsA white-coloured inorganic compound, on heating, gives a gas which turns lime water milky and residue is left which is yellow when hot and turns white on cooling. The compound is
Pb(NO3)2
PbCO3
BaCO3
ZnCO3
Prussian blue is formed when
ferrous sulphate reacts with FeCl3
ferric sulphate reacts with K4[Fe(CN)6]
ferrous ammonium sulphate reacts with FeCl3
ammonium sulphate reacts with FeCl3
Lithium is the strongest reducing agent because of
its greater hydration energy
its high ionization energy
its high electron affinity
its low electronegativity
The first ionisation potential (in eV) of N and O atoms are
14.6, 13.6
13.6, 14.6
13.6, 13.6
14.6, 14.6
Correct order for solubility of alkaline earth metals in water is
MgF2 > CaF2 > SrF2 > BaF2
MgF2 <CaF2 <SrF2 <BaF2
MgF2 > CaF2 < SrF2 < BaF2
BaF2 >MgF2 >SrF2 >CaF2
The second ionisation enthalpies of Li, Be, B and C are in order
Li > B > C > Be
Li > C > B > Be
Be > C > B > Li
B > C > Be > Li
A.
Li > B > C > Be
The ionisation enthalpy depend on the following factors.
(i) Half-filled or fully filled atomic orbitals are more stable than other incomplete orbitals.
(ii) Smaller the size of atom/ion, more is the ionisation energy (IE) For 2nd IE all elements have M+ configuraton.
| Total no.of electrons | Outermost configuration | |
| Li+(Z=3) | 2 | 1s2 (fully filled) |
| Be+(Z=4) | 3 | 2s1(has more size than carbon) |
| B+(Z=5) | 4 | 2s2 (full filled) |
| C+(Z=6) | 5 | 2s22p1 (small size) |
Hence, correct order for 2nd IE is Li+>B+>C+ >Be+ or Li > B > C > Be.
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