AdiChemistry IIT JEE

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1) Molecular formula of Glauber's salt is:

(IIT JEE 1985)

a) MgSO4.7H2O

b) FeSO4.7H2O

c) CuSO4.5H2O

d) Na2SO4.10H2O


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.

Related questions

2) Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides? 

(AIEEE 2011) 

1) K2O < Na2O < Al2O3 < MgO 

2) Al2O3 < MgO < Na2O < K2

3) MgO < K2O < Al2O3 < Na2

4) MgO < K2O < Na2O < Al2O3


* 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 < K2


Correct option is: '2'.

3) The correct order of stability for the following super oxides is:


1) KO2 > RbO2 > CsO2

2) RbO2 > CsO2 > KO2

3) CsO2 > RbO2 > KO2

4) KO2 > CsO2 > RbO2


* 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


Correct option is: '3'.

4) The correct order of stability for the following super oxides is:


1) Na2O

2) Na2O2

3) K2O

4) KO2


* The superoxide ion has an odd electron it and hence the superoxides are paramagnetic.


Correct option is: '4'.

5) The chemical formula of feldspar is: 


1) KAlSi3O8 

2) Na3AlF6 

3) NaAlO2 

4) K2SO4.Al2(SO4)3.4Al(OH)3


Feldspars are a family of aluminosilicate minerals. K2O.Al2O3.6SiO2 or KAlSi3O8 is called potassium feldspar or K-spar. It is a tectosilicate.

6) What are the products formed when Li2CO3 undergoes decomposition? 


1) Li2O2, CO 

2) Li2O, CO 

3) Li2O,CO2 

4) LiO2, CO


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

7) Among the alkali metals, the metal with the highest ionization potential is:


1) Na 

2) Li 

3) Rb 

4) Cs


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.

8) Alkali metals are: 


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.


AdiChemistry IIT JEE

(new) Click here to see 3d Interactive Solved Question paper 

Author: Aditya vardhan Vutturi