1.          
A
non-metal X exists in two different forms Y and Z.  Y is the hardest natural substance,  whereas Z is a good  conductor of electricity.   Identify X, Y and  Z.
2.          
A
solution of potassium chloride when 
mixed  with  silver 
nitrate solution, an insoluble white 
substance is formed.  Write  the chemical 
reaction involved and  also
mention the type  of the chemical  reaction ?
3.          
A
substance X, which  is an oxide  of a metal 
is used  intensively in the cement  industry. This  element is present in bones  also.  
On  treatment with  water 
it forms  a solution which  turns 
red litmus  blue.  Identify X and  also write 
the chemical  reactions involved.
4.          
What  is Plaster 
of Paris  ? How  it is obtained from  Gypsum. Write 
chemical  reaction. Give its one
use.
5.          
A
metal  A, which  is used 
in thermite process,  when  heated with 
oxygen  gives  an oxide B, which  is amphoteric in nature.  Identify A and  B. Write down the reactions of oxide  B with 
HCl and  NaOH.
6.          
Why
do we store  silver  chloride in dark  coloured bottles  ?                                                     
7.          
A
magnesium ribbon  is burnt in oxygen  to give a white  compound X accompanied by  emission of light.
(a)    
Write  the chemical 
formulae of X
(b)    
Write  a balanced chemical  equation, when X is dissolved in water.
8.          
Salt
A commonly used  in bakery  products on heating gets converted into
another salt  B which  itself is used  for removal of hardness of water and  a gas C is evolved. The gas C when passed
through lime water,  turns it milky.  Identify A,B and  C. 
Write balanced chemical  equations
for each  step.
9.          
Fill
in the missing data  in the following
table                                                                                 
10.       
(i)   Given below are the steps for extraction of
copper from its ore.  Write the
reaction  involved.
(a)       
Roasting
of copper (1) sulphide
(b)       
Reduction
of copper (1) oxide  with  copper (1) sulphide. 
(c)       
Electrolytic
refining
 (ii)    
Draw  a neat  and 
well  labelled diagram for
electrolytic refining of copper
OR 
(a)       
Explain  the formation of Magnesium Chloride by the
transfer of electrons. 
(b)       
Explain  three 
properties of ionic compounds.

 
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