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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Two non-metals combine with each other by the sharing of electrons to form a compound X. (a). What type of chemical bond is present in X? (b). State whether X will have a high melting point or low melting point. (c). Will it be a good conductor of electricity or not? (d). Will it dissolve in an organic solvent or not? |
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Answer» (a) Covalent bond (b) Low melting point (c) No (d) Yes |
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| 152. |
State the reason why (i) carbon is not used to reduce the oxides of sodium or aluminium. (ii) an iron strip dipped in a blue copper sulphate solution turns the blue solution to pale green. (iii) calcium does not occur in free state in nature. (iv) zinc is used in the galvanisation of iron and not copper. |
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Answer» (i) Both sodium and aluminium are stronger reducing agents than carbon. Therefore, carbon is not in a position to reduce the oxides of these metals to the metallic form. (b) Iron displaces copper from copper sulphate solution to form iron sulphate which imparts pale green colour to it. (iii) Calcium (Ca) is a reactive metal and is placed high in the activity series. It therefore, does not exist in free state also called native state. (iv) Zinc is placed above iron in the activity series. When deposited over its surface (galvanisation), zinc gets corroded and not iron. But copper is placed below iron and therefore, does not participate the corrosion. In this case, iron is corroded or rusted. |
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| 153. |
Name one metal and one non-metal which exist in liquid state at room temperature ? |
| Answer» Mercury (metal) and bromine (non-metal) exist as liquid at room temperature. | |
| 154. |
What changes do you observe in the iron nails and colour of copper sulphate solution if the nails are dipped in `CuSO_(4)` solution for 15 minutes ? |
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Answer» Iron nails turn to brown and the solution becomes light green because of the displacement reaction taking place in solution `Re(s) + CuSO_(4)(aq) rarr underset(("Light green"))(FeSO_(4)(aq))+ underset(("Brown"))(Cu(s))` A brown coating gets deposited on the surface of the nails. |
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| 155. |
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them? |
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Answer» This is because it is easier to obtain metals from their oxides (by reduction) than from carbonate or sulphide ores. So, before reduction the ore must be converted into metal oxide which can then be reduced. Caicination or roasting is done depending on the nature of ore, to convert the ore into oxide. A-carbonate ore is converted into oxide by caicination whereas a sulphide ore is converteq into oxide by roasting. |
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| 156. |
When a metal X is treated with cold water, it gives a basic salt Y With molecular formula XOH (molecular mass =40) and liberates a gas Z which easily catches fire. Identify X , Y and Z and also write the reaction involved. |
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Answer» Molecular formula of y = XOH Let atomic weight of metal X is a. Then, molecular mass of XOH = a + 16 + 1 = 40 (Given) a = 40 - 17 = 23 Thus, metal X is sodium (Na) because 23 is the atomic weight of sodium metal. Sodium reacts with as `2Na+underset("Cold")(2H_(2)O)toundersetY(2NaOH)+H_(2)uparrow` Sodium (Na) gives hydrogen gas (Z) on reaction with cold water. So, Y is NaOH (sodium hydroxide) Z is `H_(2)` (hydrogen gas). |
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| 157. |
Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)? |
| Answer» Nitric acid (`HNO_(3)`) is e strong oxidising agent. So, as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the nitric acid oxidises this hydrogen to water and itseiy HN03 gets reduced to `NO_(2)" or NO or "N_(2)O`. So, in the reaction of metais (except Mn and Mg), with dilute nitric acid, no hydrogen gas is evolved. | |
| 158. |
Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?A. `H_(2)SO_(4)`B. HClC. `HNO_(3)`D. All of these. |
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Answer» Correct Answer - C `HNO_(3)` is a strong oxidising agent. It oxidises metals to metal and then to metal nitrates and itself is reduced to either nitric oxide (NO), nitruos oxide `(N_(2)O)` or nitrogen dioxide `(NO_(2))`. However, both Mg and Mn evolve hydrogen on reacting with the acid. |
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| 159. |
Out of zinc and iron, which evolves hydrogen more readily on reacting with dilute HCl ? |
| Answer» Zinc evolves hydrogen more readily than iron on reacting with dilute HCl because it is placed above iron in the reactivity series. | |
| 160. |
Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?A. `H_(2)SO_(4)`B. HClC. `HNO_(3)`D. All of these |
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Answer» Correct Answer - c Nitric acid (`HNO_(3)`) does not give hydrogen gas on reacting with metals (except Mn anti Mg) because nitric acid is a strong oxidising agent so, as soon as hydrbgen gas is formed in the reaction between metal and dil. `HNO_(3)," the "HNO_(3)` oxidises this hydrogen to water. |
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| 161. |
Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam?A. FeOB. `Fe_(2)O_(3)`C. `Fe_(3)O_(4)`D. `Fe_(2)O_(3)" and " Fe_(3)O_(4)` |
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Answer» Correct Answer - c Reactions of iron metal with water `underset("Iron (II) farric")(Fe(s))+underset("Steam")(H_(2)O)tounderset("Iron (II) oxide")(FeO)+H_(2)(g)uparrow` `underset("Iron (III) farric")(2Fe(s))+underset("Steam")(3H_(2)O)tounderset("Iron (III) oxide")(Fe_(2)O_(3))+3H_(2)(g)uparrow` `3Fe(s)+4H_(2)Otounderset("Iron (II, III) oxide")(Fe_(3)O_(4))+4H_(2)(g)uparrow` |
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| 162. |
A solution of CuSO4 was kept in an iron pot. After few days the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved. |
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Answer» Iron (Fe) is placed above copper (Cu) in the reactivity series. This means that a chemical reaction had occurred between iron (iron pot) and aqueous `CuSO_(4)` solution. `Fe(s) + CuSO_(4)(aq) rarrFeSO_(4)(aq) + Cu(s)` Since iron was consumed in the reaction, a number of holes appeared in the pot. |
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| 163. |
Although metals form basic oxides, which of the following metals form an amphoteric oxide ?A. NaB. CaC. AlD. Cu |
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Answer» Correct Answer - c Aluminium (Al) metal forms amphoteric oxide `(Al_(2)O_(2))` which shows basic as well as acidic behaciour. |
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| 164. |
Which of the following elements would iield a basic oxide? `S,P,Ca,Si` |
| Answer» We know that only metal elemtns yield basic oxides. Now out of the above given elements only Ca is a metal (Ca=calcium), therefore, Ca will yield a basic oxide. The elements (S) (sulphur),P (phosphorus) and Si (silicon) are all non-metals. | |
| 165. |
Although metals form basic oxides, which of the following metals forms an amphoteric oxide ?A. NaB. CaC. ZnD. Cu. |
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Answer» Correct Answer - C Zn forms amphoteric oxide ZnO which reacts with both the acids and the alkalies. |
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| 166. |
Metal A burns in air, on heating, to form an oxide `A_(2)O_(3)` whereas another metal B burns in air only on strong beating to form an oxide BO. The two oxides `A_(2)O_(3)` and `BO` can react with hydrochloric acid as well as sodium hydroxide solution to form the corresponding salts and water. (a). What is the nature of oxide `A_(2)O_(3)`? (b). What is the nature of oxide `BO`? (c). Name one metal like A. (d). Name one etal like B. |
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Answer» (a). Amphoteric oxide (b). Amphoteric oxide (c). Aluminium , Al ltbr. (d). Zinc, Zn |
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| 167. |
An element E forms an oxide `E_(2)O`. An aqueous solution of `E_(2)O` turns red litmus paper blue. (a). What is the nature of the oxide `E_(2)O`? (b). State whether element E is a metal or a non-metal. (c). Give one example of an element like E. |
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Answer» (a). Basic oxide (b). Metal (c). Sodium, Na |
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| 168. |
A basic oxide will formed by the element:A. KB. SC. PD. Kr |
| Answer» Correct Answer - A | |
| 169. |
An element forms an oxide `A_(2)O_(3)` which is acidic in nature. Identify A as a metal or non-metal. |
| Answer» Since the oxide `A_(2)O_(3)` is acidic in nature, the element A is non-metal. | |
| 170. |
You are given a solution of `AgNO_(3)` which of the following do you think cannot displace Ag from `AgNO_(3)` solution?A. MagnesiumB. ZincC. GoldD. Copper |
| Answer» Correct Answer - C | |
| 171. |
Give reasons for the following : (i) Zinc can displace copper from copper sulphate solution. (ii) Silver articles become black after sometime when exposed to air. (iii) A metal sulphide is converted to its oxide to extract the metal from sulphide ore. |
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Answer» (i) Zinc is placed above copper in the activity series. Therefore, it can easily displace copper from copper sulphate solution `Zn(s) + CuSO_(4)(aq) rarrZnSO_(4)(aq) + Cu(s)` (ii) Air contains traces of hydrogen sulphide `(H_(2)S)`gas. Silver has a tendency to combine with `H_(2)S` to form silver sulphide `(Ag_(2)S)` which is black in colour. On account of this, silver articles become black after some time when kept exposed to air. (iii) A metal sulphide is normally converted into oxide by heating with excess of air or oxygen. This process is called roasting. Actually, the oxide of metal which is formed can be easily reduced to the metallic form by reduction with carbon or some electropositive element. `underset("Zinc sulphide")(2ZnS + 3O_(2)) overset("heat")rarr2ZnO + 2SO_(2)` `ZnO + C overset("heat")rarrZn + CO` |
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| 172. |
(a). Write one reaction in which aluminimum oxide behaves as a basic oxide and another in which it behaves as an acidic oxide. (b). What special name is given to substances like aluminium oxide. (c). Name another metal oxide which behaves like aluminium oxide. |
| Answer» (b) Amphoteric oxides ltBrgt (c). Zinc oxide | |
| 173. |
Metals X and Y can be recovered from the anode mud left behind after the electrolytic refining of copper metal. The coins made of metal X look new even after several years of use but the coins made of metal Y lose their shine gradually and get blackened soon. when metal X is alloyed with a small amount of metal Y, it becomes hard and hence suitable for making ornaments. what are metals X and Y? Also state the colour of metal X. |
| Answer» Metal X is gold and metal Y is silver, the colour of metal X (gold) is yellow: | |
| 174. |
During extraction of metals, electrolytic refining is used to obtain pure metals. (a) Suggest a suitable electrolyte also. (c ) In this electrolytic cell, where do we get pure copper after passing electric current ? |
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Answer» In the electrolytic refining of impure copper metal : (a) A rod of impure copper is used as anode while that of pure copper as cathode. (b) The electrolyte is a water soluble salt of copper. It is normally an aqueous solution of copper sulphate. (c ) On passing current, pure copper gets deposited at the cathode. It can be scrapped off later on. |
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| 175. |
During extraction of metals, electrolytic refining is used to obtain pure metals. (a) Which material will be used as anode and cathode .for refining of silver metal by this process?(b) Suggest a suitable electrolyte also. (c) In this electrolytic cell, where do we get pure silver after passing electric current? |
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Answer» (a) Thin strip of pure silver is made the cathode (It is connected to the negative terminal of the battery). And impure. silver block is made anode (it is connected-to the positiv terminal of the battery). (b) The eiectr’ yte is any salt solution of silver like `AgNO_(3)` but sodium argentocyanide `Na [Ag(CN)_(2)]` is preferred. (c) On passing eleetric current, impure metal dissolves from the anode and goes into the electrolyte solution and pure metal from the electrolyte deposits on the cathode. |
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| 176. |
(a). Name two physical properties each of sodium and carbon in which their behaviour is not as expected from their classification as metal ad non-metal respectively. (b) Name two metals whose melting points are so low that they melt when held in the hand. |
| Answer» (a). Sodium metal: Soft, low melting point,Carbon non-metal: Graphite conducts electricity, diamond has a very high melting point (b) Gallium and Cesium | |
| 177. |
In one method of rust prevention, the iron is not coated with anything.which is this method? |
| Answer» It can be done by alloying the metal with a suitable metal/non-metal. Alloy is a homogeneous mixture of more than one metal or metal and non-metal. | |
| 178. |
The ability of metals to be drawn into thin wire is known as A. ductilityB. malleabilityC. sonorosityD. conductivity |
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Answer» Correct Answer - a These are all physical properties of metals. The ability of metals to be drawn into thin wire is known as ductility. Malleability is the property which allows the metais to be hammered into thin sheets. Sonority or sonorousity is that property of metals due to which metais make sound when hit with an object. Conductivity allows heat to pass through metals easily. |
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| 179. |
The ability of metals to be drawn into thin sheets is known asA. ductilityB. malleabilityC. sonorosityD. conductivity. |
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Answer» Correct Answer - B This characteristic is known as malleability. |
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| 180. |
Write equations for the reactions of (i) iron with steam (ii) calcium and potassium with water |
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Answer» (i) Equation for the reaction of iron with steam is given below: `underset("Iron")(3Fe(s))+underset("Steam")(4H_(2)O(g))to underset("Iron (II,III) oxide")(Fe_(3)O_(4)(s))+underset("Hydrogen")(4H_(2)(g))` (ii) Equation for the reaction of calcium with water is as follows: `underset("Calcium")(Ca(s))+underset("Water")(2H_(2)O(l))to underset("Calcium hydroxide")(Ca(OH)_(2)(aq))+underset("Hydrogen")(H_(2)(g))` (iii) Equation for the reaction of potassium with water can be written as: `underset("Potassium")(2K(s))+underset("Water")(2H_(2)O) (l)to underset ("Potassium hydroxide")(2KOH(aq))+underset("Hydrogen")(H_(2)(g))` |
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| 181. |
Four metals P, Q, R and S are all obtained by the reduction of their oxides with carbon. Metal P is used to form a thin layer over the sheets of metal S to prevent its corrosion. Metal Q is used for electroplating tiffin boxes made of metal S whereas metal R is used in making car batteris. Metals Q and R form an alloy called solder. what are metals P,Q,R and S? How have you arrived at this conclusion? |
| Answer» metal P is zinc, metal Q is tin, metal R is lead, metal S is iron metal P (zinc) is used to form a thin layer on metal S (iron) to prevent its corrosion, Metal Q (tin) is used for electroplating tiffin boxes made of metal S (iron) , metal R (lead) is used in making car batteries, metals Q (tin) and R (lead) Form an alloy called slder | |
| 182. |
Which of the two metals is more reactive: copper or silver? |
| Answer» Correct Answer - Copper | |
| 183. |
A black metal oxide `XO_(2)` is used as catalyst in the preparation of oxygen gas from potassium chlorate. The oxide `XO_(2) ` is also used in ordinary dry cells. The metal oxide `XO_(2)` cannot be reduced satisfactorily with carbon to form metal X. (a) Name the metal X. (b) Name the metal oxide `XO_(2)` (c) Which reducing agent can be used to reduce `XO_(2)` to obtain metal X? (d) Name another metal which can also be extracted by the reduction of its oxide with the above reducing agent. |
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Answer» (a) Manganese (b) Manganese dioxde (c) Aluminium (d). Chromium |
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