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(IIT JEE 1985)
a) MgSO4.7H2O
b) FeSO4.7H2O
c) CuSO4.5H2O
d) Na2SO4.10H2O
Answer:
The correct option is 'd'.
Extra information:
Formula | Name | Comment |
a) MgSO4.7H2O | Epsom salt | used as bath salt, beauty product; used by gardeners in plant supplements; improves body's ability to use insulin, improves heart and circulatory system, relieves stress. |
b) FeSO4.7H2O | Green vitriol | used to treat iron deficiency; used as reducing agent to reduce chromate in cement. |
c) CuSO4.5H2O | Blue vitriol | used as fungicide, pesticide and herbicide as part of "Bordeaux mixture"; in copper plating; as a mordant in calico printing. |
d) Na2SO4.10H2O | Glauber's salt | used in the manufacture of detergents; in the Krafts process of paper pulping. |
(AIEEE 2011)
1) K2O < Na2O < Al2O3 < MgO
2) Al2O3 < MgO < Na2O < K2O
3) MgO < K2O < Al2O3 < Na2O
4) MgO < K2O < Na2O < Al2O3
Explanation:
* Basic nature of oxides increases with increase in the size of cation.
* The increasing order of cations is: Al3+ < Mg2+ < Na+ < K+
* Therefore the increasing correct order of basic strength is: Al2O3 < MgO < Na2O < K2O
Conclusion:
Correct option is: '2'.
(EAMCET 2008 MEDICAL)
1) KO2 > RbO2 > CsO2
2) RbO2 > CsO2 > KO2
3) CsO2 > RbO2 > KO2
4) KO2 > CsO2 > RbO2
Logic:
* The stability of super oxides depend on the polarizing power of the cation. Lesser the polarizing power, greater is the stability of superoxide ion.
* The polarizing power of cations of same charge decreases with increase in the size.
* Therefore, the stability of super oxides increases with increase in the size of cations.
* The increasing order of size of ions is: K+ < Rb+ < Cs+.
* The correct order of stability is: CsO2 > RbO2 > KO2
Conclusion:
Correct option is: '3'.
(EAMCET 1995 MEDICAL)
1) Na2O
2) Na2O2
3) K2O
4) KO2
Logic:
* The superoxide ion has an odd electron it and hence the superoxides are paramagnetic.
Conclusion:
Correct option is: '4'.
(EAMCET 2007 ENGINEERING)
1) KAlSi3O8
2) Na3AlF6
3) NaAlO2
4) K2SO4.Al2(SO4)3.4Al(OH)3
Answer:
Feldspars are a family of aluminosilicate minerals. K2O.Al2O3.6SiO2 or KAlSi3O8 is called potassium feldspar or K-spar. It is a tectosilicate.
(EAMCET 2002 MEDICAL)
1) Li2O2, CO
2) Li2O, CO
3) Li2O,CO2
4) LiO2, CO
Answer:
Lithium carbonate is unstable carbonate due to polarizing power of Li+. Hence it undergoes easy dissociation just like alkaline earth metal carbonates upon heating to give lithium oxide and carbon dioxide.
Li2CO3 --------> Li2O + CO2
(EAMCET 1991 ENGINEERING)
1) Na
2) Li
3) Rb
4) Cs
Answer:
The ionization potential decreases from top to bottom in a given group with increase in the size of atom. Hence 'Li' possesses highest ionization potential among alkali metals.
(EAMCET 1985 ENGINEERING)
1) Oxidising agents
2) dehydrating agents
3) reducing agents
4) All the above
Logic and Solution:
Alkali metals are strong reducing agents. They are highly electropositive elements with a great tendency to lose electrons in reactions.
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Author: Aditya vardhan Vutturi