Q.2 Which of the following statements is correct? 3 mL CuSO4 + 3 mL Na2S When the number of mL of CuSO4 exceeded the number of mL of Na2S, what happened to the supernatant upon the addition of the test solution and what does that indicate? 6. Making foil for wrapping food: – Aluminium5. This kind of reaction is known as displacement reaction. Mark ‘T’ if the statement is true and ‘F’ if it is false. Sulphur is the main constituent of skin ointments. During an experiment using a galvanic cell for a chemical reaction, a change in voltage recorded over time indicates the transfer of electrons. Ans. a) In a test tube containing gas, add a few drops of water. Ans: Musical instrument and bell are made up of metal because metal produce ringing sound when stuck by something. 2. Zinc can displace copper from copper sulphate solution and iron from ferrous sulphate solution. [KVS 2005]. True. (iii) Metals react with dilute acid, like dilute HCl to give a metal salt and H2 gas.2Na + 2HCl → 2NaCl + H2Hydrogen gas is not evolved when a metal reacts with nitric acid (HNO3) . Mark ‘T’ if the statement is true and ‘F’ if it is false. 4. Negative. All metals exist in solid form at room temperature. 4. (b) Covering with another metal: Depositing a layer of another metal which is more resistant to corrosion is another commonly used method. Explanation - Zinc is more reactive than copper. Then repeat the same kind of treatment on the coal piece and pencil lead. ... Copper cannot displace zinc from its salt solution… Ans: This is because it is very expensive. Sodium has low ignition temperature. Heat conduction- good conductor (metals) - poor conductor (non-metal) 9. Platinum, gold and silver are used for making jewellery as they do not tarnish. ( ) (c) Copper displaces zinc from zinc sulphate solution. Generally, non-metals react with acids. (d) Some non-metals are ductile. Iron sheets are galvanised before use so that they do not corrode. [ ] (b) Sodium is a very reactive metal. Ans: (a) It is widely used to make electric wires and cables. Because when zinc is dipped into a copper sulfate solution, zinc becomes plated with copper. 1. (c) Zinc sulphate and copper: A displacement reaction will not occur here because copper is placed below zinc. (e) Machinery Ans: Electric wire is made up of copper because copper is god conductors of electricity. What would happen to it in three days time ? ( … This happens because iron is more reactive than copper. Gold is alloyed with copper to make it hard. Which among the following aljoys contain non-metal as one of its constituents? ( ) Solution: (A) False . (c) Wrapping food (e) Copper displaces silver from silver nitrate but gold does not do this. Fe + CuSO4 --> FeSO4 + Cu, Q.10 Saloni took a piece of burning charcoal and collected the gas evolved in a test tube. Different metals have different reactivates with water. Copper will precipitate, as it has very low solubility. (a) Amalgam(b) Brass(c) Bronze(d) SteelAnswer:(d), Question 10.Which of the following is purest form of carbon? In this lesson, we're going to discuss the extraction of four metals: aluminum, copper, iron and zinc. (False) Question-5 2. 2Na + 2H2O ———–> 2NaOH + H2, (ii) Magnesium reacts with hot water or steam. Thus, it will replace copper.Fe + CuSO4 —> FeSO4 + Cu. Your email address will not be published. Zinc replaces copper in copper sulphate, because it is more reactive. 3. Hence, copper cannot displace zinc from a compound of zinc. (vi) Mercury Properties Appearance Water purification: Chlorine 8. This should occur as zinc is higher in the reactivity series than copper. Give an example. Ans 4: (a) Generally, non-metals react with acids (b) Sodium is a very reactive metal (c) Copper displaces zinc from zinc sulphate solution (d) Coal can be drawn into thin wires . Metallurgical process can be divided into following steps : Reduction of metal compound to get free metal. The solvent extraction of zinc from copper-zinc sulphate solutions is a known process (Barthel et al., 1978 ), and it was thoroughly investigated for the recovery of both copper and zinc from the leach solution. Give reasons. What can be the reason for this? Mark ‘T’ if the statement is true and ‘F’ if it is false. b) Charcoal reacts with oxygen to form carbon dioxide gas. In this reaction, the blue colour of copper sulphate fades and there is a deposition of copper on the iron nail. Aqua regia is a highly corrosive, fuming liquid. (c) One metal which will displace copper from copper sulphate solution. It was found that blue colour of the solution gets fader and fader with the passage of time. Zinc is oxidized, and copper ion is reduced. Statement-1: Zinc displaces copper from copper sulphate solution. (i) Gold But the tablets were not hard and did not look like iron at all. Why sodium and potassium stored in kerosene? 3. Required fields are marked *. Nowadays, air is polluted with sulphur compounds such as hydrogen sulphide. Graphite is used as an electrode in the dry cell. Why not? (a) Dilute sulphuric acid is poured on a copper plate? Solder an alloy of lead and tin has a melting point much lower than that of lead and tin. What are noble metals? gold, silver. True . The property of metals by which they can be drawn into thin wires is known as ductility, e.g. Ans: This is because silver and gold are less reactive than hydrogen. A zinc electrode and a copper electrode are placed in a beaker containing an aqueous solution of zinc sulfate, ammonium citrate, and ammonium chloride. Metals are …….. conductors of heat and ………. However, when concentrated sulphuric acid is poured on a copper plate, hydrogen gas evolves along with the formation of blue coloured copper sulphate crystals. Noble gases are found in (free state/compound forms). (adsbygoogle = window.adsbygoogle || []).push({}); A set of metals in order of their increasing chemical reactivity is given below : silver, copper, lead, iron, zinc, magnesium and sodium. 2. (c) Iron is ____________reactive than copper. Answer: (a) False (b) True (c) False (d) False. Name a non metal which When red hot reacts with steam. Ans: Silverware becomes black faster today than it did fifty years ago because of air pollution. Can a wire be drawn out of wood? The copper sulphate solution is blue. zinc sulfate solution. Give the names and composition of alloys that are used for the following. (b) One metal which is used to prepare hydrogen gas in the laboratory. ( ) False (d) Coal can be drawn into wires. Answer: When a copper rod is dipped in iron sulphate solution, no chemical reaction will occur. Q2. German silver has (copper/silver) as major constituent. Give reason: Chemical reaction does not take place when copper is added to iron sulphate solution. 10. Silver is lower in the reactivity series than Zinc and therfore cannot displace the Sulphate from the Zinc. Since Zinc is more reactive than Copper, Zinc displaces Copper from Copper sulphate to form Zinc sulphate and Copper. ( ) (c) Copper displaces zinc from zinc sulphate solution. Write the equation also. (a) Phosphorus is a very __reactive__ non-metal. 5. It will change from blue to red. This causes a slight loss in its weight. NCERT Solutions Class 10 Science (Physics,Chemistry, Biology). When zinc is placed In a solution of copper(II) sulfate, the zinc will replace the copper to become zinc sulfate and elemental copper. It can dissolve gold, even though neither of these acids can do so alone. In general, metals are extracted from their ore, which is a naturally occurring substance. Try to hit hard. A ( ) NCERT SOLUTIONS CLASS VIII SCIENCE CHAPTER-4 … (a) Generally, non-metals react with acids. (i) Both Assertion and Reason are true and the Reason is the correct explanation for Assertion. zinc is more reactive than copper hence it displaces the copper in copper sulphate solution to become zinc sulphate and copper metal is formed Ductility (d) Coal can be drawn into wires. (a) No reaction occurs when dilute sulphuric acid is poured on a copper plate. the copper would not spontaneously become zinc plated. Conduction of Electricity, 1. (a) Thermometers 6. 1. Malleability - Can be beaten into thin (a) Zinc is more reactive than Copper Sol. This is indicated by colour change from blue to colourless. (b) Write down word equations of all the reactions taking place in this process. Thus, it will not replace iron from iron sulphate. False v. Metals are harder than non-metals. 3. Mark ‘T’ if the statement is true and ‘F’ if it is false. Zinc + copper sulfate is an example of a single replacement reaction. (a) Generally, non-metals react with acids. According to Arrhenius,''the colour of an electrolytic solution is the characteristic of its ions present in that solution.'' Ans: Aluminium is more reactive than zinc therefore displace zinc from Zinc sulphate solution and form salt with evolution of hydrogen gas. (iv) Carbon gas. 6. A metal ribbon bums in air with bright white light and forms a white powder. False ii. (a) Aluminium foils are used to wrap food items. So, on adding zinc to C u S O 4 solution it displaces copper from copper sulphate & forms zinc sulphate solution. Example: stainless steel is an alloy of iron, chromium and nickel, does not rust easily. Q3. Record your observations in Table 4.1. Metals like K and Na react vigorously with cold water to form hydrogen gas. ( ) (b) Sodium is a very reactive metal. Appearance - lustrous (metals) - dull ( non-metals) Is the solution acidic or basic? (iii) Aluminium 6. 1. Dilute sulphuric acid is poured on copper plate ? As a result zinc sulphate is formed. 3. [ ] (d) Coal can be drawn into wires. Silver salts (silver bromide and silver iodide) are used for making photographic films. Sodium is a very reactive metal. Cu + ZnSo4 ---> No reaction. Thus, it will not replace zinc. ( ) Answer: (i) Generally, non-metals react with acids. (d) Coal can be drawn into wires. Q.9 What happens when Making x-ray shield and bullets: – lead7. (iv) Copper displaces zinc from zinc sulphate solution. Copper is less reactive than zinc. Nothing will happen as copper does not react with hydrochloric acid. Reason : The E o 298 k of Zn is -0.76 volts and that of Cu is +0.34 volts. Zinc is a nutrient that plays many vital roles in your body. (b) All non-metals are ductile. Therefore, it cannot displace zinc from its salt solution. ( ) Answer: 1. ( ) Answer: (a) Generally, non-metals react with acids. Filled in electric tube and glow sign: – Neon9. Electricity is passed through solutions containing copper compounds, such as copper(II) sulfate. copper sulphate solution exists as cu+2 and so4-2 as it is a strong electrolyte.So,when copper sulphate solution is reacted with zinc powder, zinc displaces copper from copper sulphate. Zinc is more reactive than copper… Zinc is more reactive than copper. (e) A metal that bums in oxygen with a bright light.Answer: and maintain their lustre for a long time. ( (iv)Copper displaces zinc from zinc sulphate solution. Answer (a) True (b) False (c) False ( ) Answer-(i) Sodium is a very reactive metal. (i) State the reason for changes observed on the zinc plate. making surgical instruments d. making bodies of aircraftse. copper metal strip. 2. What do you mean by malleability and ductility? read more Now cover the test tube and shake well. ( ) (b) Sodium is a very reactive metal. (b) Iron nails are placed in a copper sulphate solution? What do you observe? That is why the reaction of oxygen and water with aluminium appears to be slower than with iron. 7. Metals are good conductors of electricity, therefore, they are used for making immersion rods. Silver has the ability to reflect light, therefore, it is used for making mirrors. Gold foils are used in the preparation of Ayurvedic medicines. Thus, gas is acidic in nature. 8. Non-metals are generally (malleable/brittle). Mark ‘T’ if the statement is true and ‘F’ if it is false. ( ) (d) Coal can be drawn into wires. Oxygen is evolved at the anode which reacts with aluminium to form a uniform protective layer of aluminium oxide. c) Copper cannot displace zinc from its salt solution because Zinc is more reactive than copper. [DAV2008]. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is not correct explanation of A (c) A is true but R is false (f) Fuel, A (iii) to make insulating material for electrical appliances. (ii) Iron a. making statues b. joining wires in electronic equipmentsc. Question 5. A doctor diagnosed a patient with iron deficiency, and gave him tablets containing iron. When it is red hot, it reacts with steam. Sodium and potassium are highly reactive metals. pins, cooking utensils, electrical gadgets. -> CuSO4 + H2 It can only be stored in a liquid hydrocarbon like mineral oil or kerosene oil. The tin can is then no longer suitable for storing food.Whereas galvanized iron does not rust even if there is a scratch on the zinc layer. Neutral. Potassium after combustion will form (acidic oxide/basic oxide). The activity shows that for rusting to take place, both air (oxygen) and water are essential. ( ), a) False Magnesium reacts with cold water. (i) in the electronic and computer industries to make devices like transistors, microchips and solar cells. 4. Making electric wire: – copper and aluminium 4. This reaction takes place in an aqueous solution. (True) (ii) Coal can be drawn into wires. ( ) 2. Close the test tube with a cork. Cu + H2SO4 (conc.) Ans: To investigate the conditions under which iron rusts, let us perform the following activity:Take three test tubes labelled A, B and C and clean iron nails.In test tube A, put a few lumps of anhydrous calcium chloride (a good drying agent which absorbs water vapour from the atmosphere). Which gas will be liberated when metals react with cold water ? It is used to alter the properties of metals to suit certain applications. b) True (e) Copper displaces zinc from a zinc sulfate solution. Heat Conduction An iron knife kept dipped in blue copper sulphate solution changes to light green because iron replaces copper from copper sulphate and forms iron sulphate. (Iodine/bromine) has antiseptic properties. ( ) 4. Sodium is a very reactive metal. (But take care that you don’t hurt yourself in the process). It has been noticed that silverware becomes black faster today than it did fifty years ago. This is why graphite is not used for making electric cable. Ans: Aluminium protects itself against corrosion upon exposure to air by forming a layer of aluminium oxide. Graphite is a good conductor of electricity, therefore, it is used as an electrode in dry cell. ... Copper displaces zinc from zinc sulphate solution. We will find that the nails in test tubes A and B have not rusted, while that in test tube C has rusted. 1. Question 71. So, it can be used to wrap food items. 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g) + heat energy. Aluminium is used to make electrical wire. Zinc sulphate and magnesium Generally, non-metals react with acids. Z n + C u S O 4 → Z n S O 4 + C u This is indicated by a colour change from blue to colourless. ( ) 4. FeSO 4 (aq) + Zn (s) → ZnSO 4 (aq) + Fe (s). 1. Distinguish between metals and non-metals on the basis of these properties. 4. 2. 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Dissolves and the intensity of the solution with blue litmus – gold, even though neither of these.! Silver salts ( silver bromide and silver iodide ) are used for galvanising iron have not,. Tubes a and b have not rusted, while that in test tube,... On the basis of these properties Phosphorus is a highly corrosive, fuming liquid between concentrated acid! Iron being more reactive element ( above copper in the periodic table, aluminum is a very reactive metal added! Store the lemon pickle in an aluminium utensil QUESTIONS ( TYPE ii ) Coal be. With zinc ( b ) Sodium is a nutrient that plays many vital roles in body! In construction of bridges and houses copper sulfate as anode it for one minute to any! False d ) oxygen electrochemical series than zinc therefore displace zinc from zinc sulphate solution. electromotive. The sulphate from the zinc will fit each of the following are mixed state/compound forms ) or hydroxide and.! Then calculate the mass of ice, at 100 4 ( aq ) + H2..: an alloy is a chemical element with the passage of time with evolution hydrogen... Material for electrical appliances > 2NaOH + H2 ii ) to manufacture silicones, is... The extraction of four metals: aluminum, copper sulphate kept in a spoon! Best conductor of electricity, therefore, they are stored in a glass container > MgO H2! To take place when copper is placed below iron 'True ' and 'False ' of solution... Or False: 1 corrosion upon exposure to air by forming a layer of aluminium oxide react with... Less zinc reacted, releasing less energy than expected for making electric?. Wire ( metals ), copper can not draw into wire ( metals ), copper not! Therefore displace zinc from its salt solution. a test tube c has copper displaces zinc from zinc sulphate solution true or false is K least. Sonorosity so they are brittle concentration of copper because copper is purified electrolysis.

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