InterviewSolution
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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.
| 101. |
Which among the following is widely used in the match industry ?A. `N_2`B. `C`C. `P`D. `Cl_2` |
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Answer» Correct Answer - A Phosphorus is widely used in the match industry. |
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| 102. |
(a). Write the electron arrangement in (i) a magnesium atom, and (ii) an oxygen atom. (b). How many electrons are there ini the valence shell of (i) a magnesium atom, and (ii) an oxygen atom? (c) Show on a diagram the transfer of electrons between the atoms in the formation of MgO. (d) Name the solvent in which ionic compounds are generally soluble. (e). Why are aqueous solutions of ionic compounds able to conduct electricity? |
| Answer» Correct Answer - (d) Water | |
| 103. |
The metal which can be extracted simply by heating the cinnabar ore in air is:A. ZnB. CuC. AlD. Hg |
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Answer» Correct Answer - D Correct Answer - d |
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| 104. |
Name the following : (a) A metal which is preserved in kerosene (b) A lustrous coloured non-metal (c ) A metal which can melt while kept on palm (d) A metal which is poor conductor of heat. |
| Answer» (a) Sodium (b) Iodine (c ) Gallium (d) Lead | |
| 105. |
Which important properties of aluminium are responsible for its great demand in industry ? |
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Answer» The properties of aluminium metal responsible for its great demand in industry are : (i) The metal is a good conductor of electricity. (ii) The metal is not attacked by water. (iii) The metal is a powerful reducing agent. |
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| 106. |
(a) Which metal is extracted from bauxite ore? (b) Give the name of one ore of iron. Which iron compound is preent in this ore? Write its chemical formula. (c). Describe the extraction of zinc metal from its sulphide ore (zinc blende). Write equations of the reactions involved. (d) Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken. (e) name a common metal which is highly resistant to corrosion. |
| Answer» Correct Answer - (e) Aluminium | |
| 107. |
The atomic number of an element X is 19. The number of electrons in its ion `X^(+)` will beA. 18B. 19C. 20D. 21 |
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Answer» Correct Answer - A Correct Answer - a |
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| 108. |
Manganese metal is extracted from manganese dioxide by a reduction process by making use of:A. carbonB. hydrogenC. electrlysisD. aluminium |
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Answer» Correct Answer - D Correct Answer - d |
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| 109. |
An ore of manganese metal is:A. bauxiteB. haematiteC. cupriteD. pyrolusite |
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Answer» Correct Answer - D Correct Answer - d |
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| 110. |
What reaction takes place when manganese dioxide is heated with aluminium powder ? |
| Answer» `3MnO_(2)(s) + 4Al(s) rarr 3Mn(l) + 2Al_(2)O_(3)(s)` | |
| 111. |
(a) What is corrosion? (b) Name any two metals which do not corrode easily. (c) What is the corrosion of iron known as? (d) Explain why, aluminium is a highly reactive metal, still it is used to make utensils for cooking. |
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Answer» (b) gold and platinum (c) Rusting |
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| 112. |
The atomic number of an element Y is 17. The number of electrons in its ion `Y^(-)` will be:A. 17B. 18C. 19D. 20 |
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Answer» Correct Answer - B Correct Answer - b |
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| 113. |
An element X oif atomic number 12 combines with an element Y of atomic number 17 to form a compound `XY_(2)`. State the nature of chemical bond in `XY_(2)` and show how the electron configurations of X and Y change in the formation of this compound. |
| Answer» Ionic bond, The electronic configuration of X changes from 2,8,2 to 2,8: The electronic configuration of Y changes from 2,8,7 to 2,8,8 | |
| 114. |
The atomic numbers of four element P,Q,R and S are 6,10,12 and 17 respectively. Which two elements can combine to form a covalent compound?A. P and RB. Q and SC. P and SD. R and S |
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Answer» Correct Answer - C Correct Answer - c |
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| 115. |
What chemical process is used for obtaining a metal from its oxide? |
| Answer» The chemical process is known as reduction. | |
| 116. |
Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature? A. NaB. FeC. CrD. Hg |
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Answer» Correct Answer - d Mercury (Hg) is the only metal which is found in liquid state at room temperature. |
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| 117. |
(a). Name two metals which occur in nature in free state as well as in combined state. (b). Name one ore of manganese. Which compound of manganese is present in this ore? Also write, its chemical formula. (c) A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved int eh conversion of this concentrated ore into zinc metal. |
| Answer» (a) Copper and silver | |
| 118. |
(a). Name two metals which are found in nature mainly in the free state (as metallic elements) (b) name two metals which are always found in combined state. (c) What iron compound is present in haematite ore? Also write its chemical formula. |
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Answer» (a) Gold and platinum (b) Sodium and Magnesium |
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| 119. |
(a). The atomic number of sodium is 11. What is the number of electrons in `Na^(+)`? (b). The atomic number of chlrine is 17. What is the number of electrons in `Cl^(-)`? |
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Answer» (a) 10 (b) 18 |
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| 120. |
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be (a) (b) (c) (d) |
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Answer» (a) calcium Explanation: Calcium reacts with oxygen to give an ionic compound, calcium oxide, having a high melting point. This calcium oxide compound is soluble in water. Carbon reacts with oxygen to form carbon dioxide, which is a gas. Silicon reacts with oxygen to form a compound silicon dioxide which has high melting point but insoluble in water. Similarly iron with oxygen to form iron (III) oxide compound which has a high melting point but insoluble in water |
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| 121. |
Define the following terms. (i) Mineral (ii) Ore (iii) Gangue |
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Answer» (i) Mineral: The naturally ocurring compounds of element are known as Mineal. (ii) Or: Minerals from which metals can be extractred profitably are known as ores. (iii) Gangue: The impurities present in the ore such as sand, rocks etc are nonas gangue. |
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| 122. |
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be (a) calcium (b) carbon (c) silicon (d) ironA. calciumB. carbonC. siliconD. iron |
| Answer» Correct Answer - (a) calcium. | |
| 123. |
How will you account for the high melting points of salts ? |
| Answer» The high melting points of salts are due to their closely packed structures and also due to stronger forces of attraction in the oppositely charged ions. | |
| 124. |
Why do ionic compounds have high melting points? |
| Answer» Ionic compounds have strong electrostatic forces of attraction between the ions. Therefore, It requires a lot of energy to overcome these forces. That ionic compounds have light melting points. | |
| 125. |
State and explain the reactions, if any, of the following metals with a solution of copper sulphate (a). Gold (b). Copper (c). Zinc (d). Mercury. |
| Answer» (a). No displacement reaction with gold because gold is less reactive than copper (b) No reaction of copper with copper sulphate solution (c) Zinc displaces copper from copper sulphate solution to form zinc sulphate solution and copper metal because zinc is more reactive than copper (d) No displacement reaction with mercury because mercury is less reactive than copper | |
| 126. |
What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place. |
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Answer» When zinc is added to a solution of iron (II) sulphete, then the greenish colour of iron (II) sulphate solution fades gradually due to the formation of colourless zinc sulphate solution, and iron metal is deposited on zinc: `underset("Iron (II) sulphate (Greenish solution)")(FeSO_(4)(aq))+underset("Zinc (Silvery-white)")(Zn(s))tounderset("Zinc sulphate (Colourless solution)")(ZnSO_(4)(aq))+underset("Iron (Grey)")(Fe(s))`. |
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| 127. |
Which of the following metals exist in their native state in nature ? (i) Cu (ii) Au (iii) Zn (iv) AgA. (i) and (ii)B. (ii) and (iii)C. (ii) and (iv)D. (iii) and (iv) |
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Answer» Correct Answer - C Both Au and Ag are very little reactive. For example, Argentite or silver (I) suphide `(Ag_(2)S)`. |
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| 128. |
Which of the followmg metals exist in their native state in nature? A. I and iiB. I and iiiC. ii and ivD. iii and iv |
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Answer» Correct Answer - c Gold and sitver (Au and Ag) are less reactive metals, so they are usually found in free state (native state) in nature. |
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| 129. |
Which of the followmg metals exist in their native state in nature? A. Ag and HgB. Ag and ZnC. Au and HgD. Au and Ag |
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Answer» Correct Answer - D Correct Answer - d |
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| 130. |
An alloy isA. an element B. a compoundC. a homogeneous mixtureD. a heterogeneous mixture |
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Answer» Correct Answer - c An alloy is a homogeneous mixture of different metals or a metal and a non-metal. |
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| 131. |
2 mL each of conc. HCl, `HNO_(3)` and a mixture of conc. HCl and conc. `HNO_(3)` in the ratio of3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C. The metal could be A. AlB. AuC. CuD. Pt |
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Answer» Correct Answer - b,d A mixture of cone. HOl and cone. `HNO_(3)` in the ratio of 3 : 1 is known as aqua-regia. Gold (AU) and platinum (Pt) dissolve only in aqua-regia. |
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| 132. |
5 mL each of concentrated HCl, `HNO_(3)` and a mixture of concentrated `HNO_(3)` (5 mL) were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube. The metal could beA. AlB. AuC. CuD. Ag |
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Answer» Correct Answer - B A mixture conc. HCl and conc. `HNO_(3)` (3 : 1 by volume is known as Aqua Regia. It dissovles metal Gold. |
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| 133. |
Metallic oxides of zinc, magnesium and copper were heated with the following metals. In which cases will you find displacement reactions taking place? |
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Answer» Magnesium (Mg) will displace both zinc (Zn) and copper (Cu) from their oxides Mg + ZnO `rarr` MgO + Zn Mg + CuO `rarr` MgO + Cu Zinc will displace copper from copper oxide. Zn + CuO `rarr` ZnO + Cu Copper is least reactive and will not initiate displacement reaction. |
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| 134. |
(a). Arrange the following metals in order of their chemical reactivity, placing the most reactive metal first: magnesium, copper, Iron, sodium, Zinc, Lead, Calcium. (b). What happens when a rod fo zinc metal is dipped into a solution of copper sulphate? Give chemcial equation fo the reaction involved. |
| Answer» (a). SodiumgtCalciumgtMagnesiumgtZincgtIrongtLeadgtcopper | |
| 135. |
Which metal becomes black in the presence of hydrogen sulphide gas in air? |
| Answer» Correct Answer - Silver | |
| 136. |
name the gas in air which tarnishes silver articles slowly. |
| Answer» hydrogen sulphide | |
| 137. |
Name an alloy of (i) Aluminium used in construction of air crafts. (ii) Lead in joining metals for electric welding. (iii) Copper used in household vessels. |
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Answer» (i) The alloy is duralumin : Al (95%), Cu (4%), Mg (0.5%), Mn (0.5%). (ii) The alloy is solder : Pb (50%), Sn (50%) (iii) The alloy is brass : Cu (80%), Zn (20%). |
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| 138. |
On placing a piece of zinc metal in a solution of mercuric chloride, it acquires a silvery surface but when it is placed in a solution of magnesium sulphate, no change is observed. State the reason for the behaviour of zinc metal. |
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Answer» Zinc lies above mercury in the activity series and can easily replace it from mercuric chloride solution. Mercury formed in the reaction gets deposited on the surface of zinc to give it a silvery look. `Zn(s) + HgCl_(2)(aq) rarr ZnCl_(2)(aq) + Hg(s)` But zinc is placed below magnesium in the activity series. Therefore, no chemical reaction occurs between zinc and magnesium sulphate solution. |
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| 139. |
(a) Give reasonwhy copper is used to make hot water tanksbut steel (an alloy of iron) is not. (b). Explain why, the surface of some metals acquires a dull appearance when exposed to air for a long time. |
| Answer» (a) Copper does not corrode easily in the presence of water but steel rusts in the presence of water. | |
| 140. |
Stainless steel is very useful material for our life. In stainless steel,iron is mixed withA. Cu and CrB. Cr and NiC. Cr and SnD. Cu and Ni |
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Answer» Correct Answer - B Correct Answer - b |
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| 141. |
If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of A. hydrated copper sulphateB. copper oxideC. basic copper carbonateD. copper nitrate |
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Answer» Correct Answer - C Correct Answer - c |
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| 142. |
Why can we use gold and platinum in jewellery ? |
| Answer» Both these metals are very hard, malleable and ductile. Since they lie at the bottom of the activity series, they have very low reactivity. As a result, these metals do not lose lustre and are used in jewellery. | |
| 143. |
Give reasons (a) Platinum, gold and silver are used to make jewellery. (b) Sodium, potassium and lithium are stored under oil. (c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. (d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction. |
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Answer» These metals placed at the bottom of the activity series are very little reactive in nature. Gold and platinum are known as noble metals. They are not affected by air, water and by chemicals. Since they have bright lustre, jewellery can be made from these metals. (b) There are reactive metals placed high in the activity series. In air, their surface gets tarnished due to presence oxygen, water vapours and carbon dioxide in air. With water, these react violently to evolve so much heat that is not possible to handle them. These metals are generally kept under kerosene which does not contain air and water. (c ) When exposed to air, the metal changes its oxide called aluminium oxide `(Al_(2)O_(3))`. It gets deposited over the surface of the metal and forms a protective coating on the surface. Due to the presence of this layer, the metal becomes unreactive and can be used in making cooking utensils. (d) Both carbonate and sulphide ores of metals cannot be directly reduced to metallic state. However, metal oxides can be easily reduced with coke or other reducing agents. Both are therefore, converted into their respective oxides by calcination process (for carbonate ores) and by roasting process (for sulphide ores). For chemical equations, consult section 3.11. Metal oxides can be easily reduced to metallic form with coke (C ) or any other suitable reducing agent. Therefore, carbonates and sulphides are converted to the oxide form by process of calcination and roasting and are not directly reduced. |
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| 144. |
State whether the followig statement is true or false: The Aquous solution of an ionic compound conducts electricity because there are plenty of free electrons in the solution. |
| Answer» False (it should be ions in palce of electrons) | |
| 145. |
A copper coin is kept immersed in a solution of silver nitrate for some time. What will happen to the coin and the colour of the solution? |
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Answer» (a) A coating of silver was slowly deposited on the copper coin. (b) Solution turned to blue. `Cu(s) + 2AgNO_(3)(aq) rarr underset(("Blue"))(Cu(NO_(3))_(2)) (aq) + 2Ag(s)` |
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| 146. |
You are given a hammer, a battery, a bulb, wires and a switch. (a) How could you use them to distinguish between samples of metals and non-metals? (b) Assess the usefulness of these tests in distinguishing between metals and non – metals. |
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Answer» (a) (i) Try to beat the given samples with the help of a hammer. The sample which can be easily coverted into flat sheets is malleable and represents metal. The sample which breaks is brittle and is a non-metal. (ii) Construct an electical circuit with the help of bulb, wires and a switch as shown in the Fig 3.3. Now, place the two samples one by one in the circuit. Switch on the battery. The sample which allows the bulb to glow is of a metal while the one which does not, represents a non-metal. From these tests, we may conclude that • Metals are malleable while non-metals are not. • Metals are good conductors of electricity while non-meals are not (graphite is an exception). |
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| 147. |
In a solution of silver nitrate, a copper plate was dipped. After some time, silver from the solution was deposited on the copper plate. Which metals is more reactive-copper or silver? how? |
| Answer» We know that a more reactive metal displaces a less reactive metal from its salt solution here, copper metal is displacing siolver from silver nitrate solution (which then gets deposited on copper plate), therefore, copper metal is more reactive than silver metal. | |
| 148. |
What type of bonds are present in methane `(CH_(4))` and sodium chloride `(NaCl)`? |
| Answer» Methane: Covalent bonds: Sodium chloride: Ionic bonds. | |
| 149. |
In a solution of lead acetate, a strip of metal M was dipped. After some time, lead from the solution was deposited on the metal strip. Which metal is more reactive, M or lead? |
| Answer» M is more reactive | |
| 150. |
Which of the following has a triple bond as well as single bonds?A. etheneB. methaneC. ethyneD. nitrogen |
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Answer» Correct Answer - C Correct Answer - c |
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