1 MARK QUESTIONS
Q1. Name two metals which react with dil.HNO3 to evolve hydrogen gas.
Q2. Name one metal which forms an amphoteric oxide.
Q3. Name a solvent in which electrovalent compounds are soluble and a solvent in which they are not.
Q4. Show the formation of MgO by the transfer of electrons in the two elements using electron dot structures.
Q5. Why does calcium float in water?
Q6. Name any two alloys whose electrical conductivity is less than that of pure metals.
Q7. Name one metal and one non-metal which exists in liquid state at room temperature.
Q8. Make a distinction between metals and non-metals with respect to the nature of their oxide.
Q9. Why is carbon not used for reducing aluminium from aluminium oxide?
Q10. Why ionic compounds do not conduct electricity in solid state although they are made up of ions?
Q11. Which of the following elements is a metal?
Q12. For the reduction of metal oxide to metal, suggest a reducing agent cheaper than aluminium.
Directions (Q. Nos. 13-17) In the following questions a statement of Assertion is followed by a statement of Reason. Mark the correct choice as
(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are true but Reason ·is not the correct explanation of Assertion.
(c) If Assertion is true but Reason is false.
(d) If Reason is true but Assertion is false.
(e) If both Assertion and Reason are false.
- Assertion: Iron can be obtained from Fe2O3 by reduction with aluminium.
Reason: The process is known as thermite process.
- Assertion: Elements Pt, Ag, noble gases, etc. occur in native state in nature.
Reason: Elements which are attacked by moisture, oxygen and CO2 of air occur in native state.
- Assertion: Reactivity Series is an arrangement of element based on their reactivity.
Reason: Reactivity Series is used to separate elements based on their reactivity.
- Assertion: Bauxite is the most important ore of Aluminium.
Reason: Carbon is used to reduce bauxite to aluminium.
- Assertion: Brass is an alloy of Zinc and Magnesium.
Reason: Alloys are homogenous mixture of two or more metals.
Q18. Select odd one out from the following elements.
Q19. Which element is present at the top of the reactivity series and is stored in kerosene oil?
3 MARK QUESTIONS
Q1. Why Sodium forms Sodium Hydroxide when reacting with water whereas Aluminium forms only Aluminium Oxide?
Q2. What happens when:
(i) ZnCO3 is heated in the absence of oxygen?
(ii) a mixture of Cu2O and Cu2S is heated?
Q3. Why the reduction process is always involved in the extraction of metals?
Q4. State the property utilised in the following:
(i) Graphite in making electrodes.
(ii) Electrical wires are coated with Polyvinyl Chloride (PVC) or a rubber-like material.
(iii) Metal alloys are used for making bells and strings of musical instruments.
Q5. A, B and C are 3 elements which undergo chemical reactions according to the following equations:
(a) A2O3 + 2B → B2O3+ 2A
(b) 3CSO4 + 2B → B2 (SO4)3 + 3C
(c) 3CO + 2A → A2O3+ 3C
Answer the following questions:
(i) Which element is most reactive?
(ii) Which element is least reactive?
(iii) State the type of reaction listed above.
Q6. Compound P and aluminium are used to join railway tracks.
(i) Identify the compound P.
(ii) Name the reaction.
(iii) Write the equation for it.
Q7. An ore on heating in air produces Sulphur Dioxide.
(i) Which process would you suggest for its concentration?
(ii) Describe briefly any two steps involved in the conversion of this concentrated ore into related metal.
Q8. State reason for the following:
(i) Non-metals cannot displace hydrogen from the acids.
(ii) Hydrogen is not a metal, yet it is placed in the activity series of metals.
(iii) Aluminium is more reactive than iron, yet its corrosion is less than that of iron.
Q9. (a) List in tabular form any three chemical properties on the basis of which metals and non-metals are differentiated.
(b) State two ways to prevent the rusting of iron.
Q10. Define alloys. List the properties of alloys that make them useful over pure metals? Explain this fact with suitable examples.
Q11. What is cinnabar? How is a metal extracted from cinnabar? Explain briefly.
Q12.Giving one example of each. Explain the method of obtaining the following metals from their compounds.
Metal ‘X’, which is low in the activity series.
Metal ‘Y’, which is in the middle in the activity series.
Metal ‘Z’, which is towards the top of the activity series.
Q13. Write chemical equations for reactions taking place when
(a) Manganese Dioxide is heated with aluminium powder.
(b) Steam is passed over hot iron.
(c) Magnesium is treated with dil.HNO3 .
Q14. Give reasons for the following:
(a) Metals are regarded as electropositive elements.
(b) When a piece of copper metal is added to a solution of zinc sulphate, no change takes place but the blue colour of copper sulphate fades away when a piece of zinc is placed in its solution.
(c) Articles made of aluminium do not corrode even though aluminium is an active metal.
Q15. What is corrosion of metals? Name one metal which does not corrode and one which corrodes on being kept in open atmosphere.
Q16. Zn is more electropositive than Fe. Therefore, it should get corroded faster than Fe. But it does not happen. Instead, it is used to galvanise Iron. Explain why?
Q17. Why Al metal cannot be obtained by the reduction of Al2O3 with coke? Explain.
Q18. List three properties of sodium in which it differs from the general physical properties of most of the metals.
5 MARKS QUESTION
Q1. (i) Predict the reaction, if any, between
(a) Zinc and Silver Nitrate solution,
(b) Magnesium and Iron (II) Chloride solution,
(c) Copper and Magnesium Sulphate solution.
Write the equations, with its physical form symbols, for the reaction.
(ii) A lump of element X can be cut by a knife. During its reaction with water, X floats and melts. What is X? Explain.
Q2. (a) Define the terms ‘alloy’ and ‘amalgam’. Name the alloy used for welding electric wires together. What are its constituents?
(b) Name the constituents of the following alloys:
(i) Brass (ii) Stainless steel (iii) Bronze,
State one property in each of these alloys, which is different from its main constituents.
Q3. (i) Name the method used to extract metals of high reactivity.
(ii) Name the main ore of mercury. How is mercury obtained from its ore? Give balanced chemical equations.
(iii) Explain what is thermite reaction with the help of balanced equation. How is it used to join railway tracks or cracked machine parts?
Q4. (a) An ore on treatment with dilute hydrochloric acid produces brisk effervescence. What type of ore is this? Write the steps required to obtain metal from the enriched ore.
(b) An ore on heating in air gives sulphur dioxide gas. Name the method in each metallurgical step, that will be required to extract this metal from its ore.
Q5. Give reason for the following :
(a) Ionic compounds have high. melting and boiling points.
(b) Non-metals, in general, do not displace hydrogen from dilute acids.
(c) Hydrogen gas is not evolved, when zinc metal reacts with dil. HNO3
(d) School bells are made up of metals.
(e) Oxides of highly reactive metals cannot be reduced by carbon.
Q6. (i) An ore, on heating in air, give sulphur dioxide gas. Name the method in each metallurgical step, that will be. required to extract this metal from its ore.
(ii) State which of the following reactions will take place or which will not, giving suitable reason for each?
Zn(s)+CuSO4 (aq) → ZnSO4 (aq)+Cu(s)
Fe(s) + ZnSO4 (aq) → FeSO4 (aq) + Zn(s)