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(AIEEE 2003 - EQUIVALENT TO IIT JEE MAIN)
1) lattice energies of solids
2) hydration energies of cations
3) inter-ionic attraction
4) entropy of solution formation
Solubility of an ionic compound in water decreases with increase in lattice energy but increase with hydration energies.
In alkaline earth metal group, the hydration energy of cation decreases from top to bottom with increase in the size of cation. However, the lattice energy remains almost unchanged.
Option 2 is correct.
1) Ca2+ < Mg2+ < Be2+ < K+
2) Mg2+ < Be2+ < K+ < Ca2+
3) Be2+ < K+ < Ca2+ < Mg2+
4) K+ < Ca2+ < Mg2+ < Be2+
* Polarizing power = charge on the ion / size of the ion
i.e. the polarizing power is directly proportional to charge and inversely related to size of the ion.
* The decreasing order of size of cations is: K+ > Ca2+ > Mg2+ > Be2+
* Therefore the increasing correct order of polarizing power is: K+ < Ca2+ < Mg2+ < Be2+
Correct option is: '4'.
(EAMCET 2006 ENGINEERING)
1) Mg2+, K+
2) Al3+, Na+
3) Na+, Mg2+
4) Zn2+, Mg2+
Carnallite is KCl.MgCl2.6H2O. It shows presence of K+ and Mg2+ ions in aqueous solutions.
(EAMCET 1998 ENGINEERING)
1) Plaster of Paris + Silica
2) Slaked lime + Plaster of Paris + H2O
3) CaCO3 + Silica + H2O
4) Slaked lime + sand + H2O
Lime mortar is a mixture of one part of Slaked lime (Ca(OH)2), three parts of Sand (SiO2) and water. It is converted into calcium silicate with time and becomes hardened. Hence it is used as building material.
Ca(OH)2 + SiO2 --------> CaSiO3 + H2O
1) BaCO3 > CaCO3 > SrCO3 > MgCO3
2) BaCO3 > SrCO3 > CaCO3 > MgCO3
3) MgCO3 > CaCO3 > SrCO3 > BaCO3
4) MgCO3 > CaCO3 > BaCO3 > SrCO3
Logic and Solution:
If the carbonate ion is polarized by the cation, it undergoes decomposition easily upon heating. The polarizing power of alkali metal cations decreases with increase in the size.
i.e. the order of polarizing power of cations is:
Mg2+ > Ca2+ > Sr2+ > Ba2+
Hence the correct order of thermal stability of carbonates will be:
BaCO3 > SrCO3 > CaCO3 > MgCO3
1) a marble statue
2) calcined gypsum
3) sea shells
* Marble, sea shells and dolomite contain calcium carbonate.
* Dolomite is CaCO3 + MgCO3
* Calcined gypsum is dehydrated gypsum otherwise known as plaster of paris. It does not contain any calcium carbonate.
(EAMCET 1996 E)
1) Mg + Zn
2) Mg + Al
3) Cu + Zn
4) Mg + Cu
Magnalium is an alloy of magnesium (1.5 - 2%) and aluminium metals. Due to high strength, low density and ability to resist corrosion; it is used in amking aircraft and automobile parts.
(EAMCET 1999 E)
The gas in the container is carbon sicne magnesium can reduce carbon dioxide to carbon.
2Mg + CO2 ---------> 2MgO + C
(new) Click here to see 3d Interactive Solved Question paperAuthor: Aditya vardhan Vutturi