Chemical reaction and equations Quiz- 1

Chemical reactions and equations

Quiz

 

1. An element ‘X’ displaces iron from the aqueous solution of iron sulphate. List your observations if the element ‘X’ is treated with the aqueous solutions of copper sulphate, zinc sulphate and silver nitrate. Based on the observations arrange X, Zn, Cu and Ag in increasing order of their reactivities.
   1.   Ag < Cu < Zn < X
   2.   Ag < Cu > Zn < X.
   3.   Cu < Zn < X< Ag
   4.   X<Cu < Zn < Ag
2. Reaction of 'magnesium' with air is
   1.   Exothermic reaction
   2.   Endothermic reaction
   3.   Reversible reaction
   4.   Substitution reaction
3. In writing chemical equations, inclusion of state symbols shall be done while
   1.   Correct chemical formulae of reactants and products are written
   2.   The equation is being balanced to fulfill the law of conservation of mass
   3.   The equation has been balanced
   4.   The chemical formulae of products and reactants have been changed to bring about quick balancing
4. The reaction in which two compounds exchange their ions to form two new compounds is called
   1.   Displacement reaction
   2.   Combination reaction
   3.   Double displacement reaction
   4.   Redox reaction
5. On immersing an iron nail in CuSO₄ solution for a few minutes, you will observe
   1.   No reaction takes place
   2.   The color of solution fades away
   3.   The surface of iron nails acquire a black coating
   4.   The color of solution changes to green
6. Which of the given statements is not a physical change?
   1.   Boiling of water to give water vapour
   2.   Melting of ice to give water
   3.   Dissolution of salt in water
   4.   Combustion of Liquefied Petroleum Gas (LPG)
7. In which of the given, heat energy will be evolved?
   1.   Electrolysis of water
   2.   Dissolution of NH₄Cl in water
   3.   Burning of L.P.G.
   4.   Decomposition of AgBr in the presence of sunlight
8. When crystals of lead nitrate are heated strongly in a dry test tube
   1.   Crystals immediately melt
   2.   A brown residue is left
   3.   White fumes appear in the tube
   4.   A yellow residue is left
9. Paheli Is Writing Some Statement Which Is Given By Her Teacher. Would You Help Him To Choose The Incorrect Statements?
   1.   The combustion reaction of candle wax is characterized by a change in state from solid to liquid and gas.
   2.   When a chemical reaction absorbs heat energy, then the temperature of reaction mixture is falls and it becomes cold.
   3.   When a Zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas.
   4.   None of the above.
10. Which Of The Following Statement Is Or Are Incorrect?
    1.   The burning of magnesium in air to form magnesium oxide.
    2.   The properties of the product magnesium oxide are entirely different from the reactants.
    3.   The chemical reaction between sodium carbonate and dilute
    4.   None of the above
11. Magnesium ribbon is rubbed before burning because it has a coating of
    1.   basic magnesium carbonate
    2.   basic magnesium oxide
    3.   basic magnesium sulphide
    4.   basic magnesium chloride
12. Which of the following statements about the given reaction are correct?
    3Fe (s) + 4H2O (g) → Fe3O4 (s) + 4 H2 (g)
    (i) Iron metal is getting oxidised
    (ii) Water is getting reduced
    (iii) Water is acting as reducing agent
    (iv) Water is acting as oxidising agent
    1.   (i), (i) and (iii)
    2.   (i) and (iv)
    3.   (i), (ii) and (iv)
    4.   (ii) and (iv)
13. MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
    Identify the substance oxidized in the above equation.
    1.   MnCl2
    2.   HCl
    3.   H2O
    4.   MnO2
14. A substance ‘X’ is used in white-washing and is obtained by heating limestone in the absence of air. Identify ‘X’.
    1.   CaOCl2
    2.   Ca (OH)2
    3.   CaO
    4.   CaCO3
15. Select the oxidising agent for the following reaction:
    H2S + I2 → 2HI + S
    1.   I2 (Iodine)
    2.   H2S
    3.   HI
    4.   S