1. Potato Chips manufactures fill the packet of chips with nitrogen gas. Why ?
2. An element A forms two oxides AO and AO2. The oxide AO is neutral whereas the oxide AO2 is acidic in nature. Would you call element A a metal a non-metal.
3. A small amount of ferrous sulphate were heated in a hard glass test tube?
(i) Write the equations involved in the above reaction
(ii) What type of reaction is taking place ?
4. What is a redox reaction? Write down a chemical equation representing it.
7. A metal is treated with dil H2S04 the gas evolved is collected by the method shown in the figure. Answer the following
(i) Name the gas. (ii) Name the method of collection of the gas. (iii) Is the gas soluble or insoluble in water? (iv) Is the gas lighter or heavier than air ?
5. Differentiate between roasting and calcination process giving an example of each.
6. A brown substance ‘X’ on heating in air forms a substance ‘Y’. When hydrogen gas is passed over heated ‘Y’, it again changes back into ‘X’.
(i) Name the substance X and Y.
(ii) Name the chemical processes occurring during both the changes.
(iii) Write the chemical equations.
7. What is neutralisation reaction ? Give two examples.
8. A compound which is prepared from Gypsum has the property of hardening when mixed with proper quantity of water.
(i) Identify the Compound.
(ii) Write the chemical equation for its preparation.
(iii) Mention one important use of this compound.
9. Four metals A,B,C and D are in turn added to the following solutions one by one. The observations made are tabulated below.
Metal Iron (II) sulphate Copper (II) Sulphate Zinc sulphate Silver nitrate
A No reaction Displacement
B Displacement No reaction
C No reaction No reaction No reaction Displacement
D No reaction No reaction No reaction No reaction
Answer the following questions based on the above information.
(i) Which is the most active metal and why ?
(ii) What would be observed if B is added to a solution of copper sulphate and why.
(iii) Arrange the metals A,B,C and D in order of increasing reactivity.
(iv) Container of which metal can be used to store both Zinc sulphate solution and silver nitrate solution.
(v) Which of the above solutions can be easily stored in a container made up of any of these metals.
OR
Design an activity to show the conditions needed for iron nails to rust. Why do we apply paint on iron articles ?
10. Reddish brown deposit obtained on iron nails when kept in a solution of CuSO4 in water is that of
(a) Cu2O (b) CuO (c) Cu (d) CuS
11. When crystals of FeSO4 are strongly heated the residue obtained is :
(a) red in colour (b) blue in colour
(c) green in colour (d) colourless.
12. When CO2 is passed through lime water, milkiness is formed is due to :
(a) CaCO3 (b) Ca(OH)2
(c) Ca(HCO3)2 (d) none of these
13. In a sample of distilled water a pinch of solid sodium carbonate is dissolved in it. The pH will be:
(a) Less than 7 (b) More than 7 (c) Exactly 7 (d) very near to 7
14. A few drops of liquid ‘X’ were added to distilled water. It was observed that pH of the water is increased. The liquid ‘X’ is:
(a) lemon juice (b) NaCl solution
(c) Na2CO3 solution (d) dilute HCl solution
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