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Which of the following gas is produced during the decomposition of lime stone into lime (calcium oxide)?
a) nitrogen                                            

b) hydrogen
c) carbon dioxide                              

d) oxygen

c

Commercially sodium is obtained from which of the following molten salt?
a) Na2CO3                                            

b) NaCl
c) NaO                                  

d) NaHCO3

b

Which of the following type of reaction takes when electricity is passed through molten NaCl, and produce sodium and chlorine?
a) combustion                     

b) displacement
c) double-displacement     

d) decomposition

d

A chemical reaction in which a more reactive element takes the place of a less reactive element in a compound is called ……reaction.
a) burning                                             

b) displacement
c) double-displacement     

d) addition

b

Explanation:A single-displacement reaction is a reaction in which one element replaces a similar element in a compound. The general form of a single-displacement (also called single-replacement) reaction is:A+BC→AC+B


Which of the following reaction show displacement reaction?
a) C(s) + O2(g) ------
à CO2(g)                                                
b) Zn(s) + H2SO4(aq) -----
à ZnSO4(aq) + H2(g)
c) 4Ag(s) + O2(g) ------à 2Ag2O(s)            
d) 2Ca(s) + O2(g)------
à 2CaO(s)

b

Iron can be extracted from iron oxide by heating with…….
a) water                                

b) hydrogen
c) oxygen                                             

d) coke (carbon)

d