Assignment – 4
Chemical Reactions And Equations

Q 1. What is the Colour of magnesium?

Q 2. Why it is Recommended always to use Dilute Acids?


Q 3. What is Wafting gas?


Q 4. Why AgCl kept in a Black colour of Bottle?

Q 5. What do you mean by Photolytic Docomposing. Explain with their Reaction?

Q 6. Which Reaction is Used for Black and White Photography?

Q 7. Why does the Iron nail become brownish in colour and the blue colour
of copper sulphate solution fade?

Q 8. Write the chemical formula for the following.
Ammonium chloride, ammonium nitrate, chlorine, dilute hydrochloric acid, iron, lead nitrate, manganese (IV) oxide, silver nitrate, sodium nitrate, sodium nitrite, Calcium Carbonate, Calcium Hydroxide, Sulphuric acid, Nitric acid, Copper Sulphate, Calcium Sulphate.

Q 9. Fill in the following about reactivity series of metal : The …………………. Metal replaces the ………………. Metal from its salt solution.

Q 10.  Which of the following is not the necessary condition for rusting (i) Presence of oxygen (ii) Presence of catalyst (iii) Presence of moisture

Q 11. Choose the correct about rancidity (i) Rancidity is a reduction process (ii) Rancidity is an oxidation process
  
Q 12. When silver coloured metal (A) is added to dilute sulphuric acid, solution (B) is formed which is colourless solution and a gas (c) is evolved which is colourless name ‘A’, ‘B’ and ‘C’ and write the equation?

Q 13. An ‘A’ blue coloured crystalline salt on heating decomposes to ‘B’ white substance. When in blue salt solution, a metal (Zinc) is added, its gives rise to colourless solution ‘C’ with leaving behind ‘D’ reddish brown metal. Name the compounds ‘A’, ‘B’, ‘C’ and ‘D’

Q 14. A mixture of Chromium Oxide is heated with Aluminium powder on strong heat:   a. Write the reaction? b. Give one application of this reaction?

Q 15. Choose and state as true or false
ü  In exothermic reaction heat is evolved. True / False
ü  Decomposition is possible by thermal decomposition, electrolytic decomposition and by photo chemical decomposition. True / False
ü  Displacement reaction of metals is based on reactivity series of metals. True / False
ü  Oxidising agent is a substance which causes addition of oxygen or removal of hydrogen from other substance. True / False
ü  Reduction is a process which involves removal of hydrogen and addition of oxygen. True / False

Q16. Give a word to fill in the blank
ü  Substance which causes addition of oxygen or removal of hydrogen from other substance is ………………..agent.
ü  Presence of air, presence of moisture, presence of salt in water, electropositive metals leads a metal to ………
ü  ……………metals are less electropositive and hence they do not corrode in moist air.
ü  A reaction in which an insoluble product formed during the reaction of two ionic compounds in aqueous solution is called ………...
ü  A substance which causes addition of Hydrogen or removal of Oxygen from other substance is called ………….
ü  The arrangement of elements in decreasing order of their electro positive character is called ………....
ü  When sodium metal is added to water, it gets …….…..
ü  In the order of decreasing order of reactivity in Ca > Al > Zn > H > Ag > Pt The most reactive metal is ………….
ü  In the order of decreasing order of reactivity as stated above the least reactive metal is ...................
ü  In the order of Ca > Al > Zn > H > Ag > Pt Choose the metal which from above can react with all the salt solutions. ………

Q 17. Why do we preserve Sodium metal in kerosene oil?

Q 18. What happens when we heat coloured crystalline copper sulphate?

Q 19. In electrolysis of water, on which electrode hydrogen migrates and why?

Q 20. What happens when quick lime is added to water? Name the reaction and compounds formed.