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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.
| 201. |
Write the reactionsat the cathode and at the anode during electrolysis of copper sulphate using copper electrode. |
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Answer» SOLUTION :(a) `Cu^(2+) (AQ) +2e^(-) to Cu(s) ` (b) `4OH^(-) to 2H_(2)O +O_(2)+4e^(-)`. |
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| 202. |
The size of potassium atom is greater than the size of sodium atom. Give reason. |
| Answer» Solution :Because in potassium (K = 2, 8, 8, 1) the OUTERMOST electron is in the fourth shell (N-shell, n = 4), whereas in sodium (Na = 2, 8, 1) the outermost electron is in the third shell (M-shell, n = 3). | |
| 203. |
What type of changes are observed during chemical reaction ? |
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Answer» Solution :The following CHANGES are OBSERVED during chemical reaction : (1) Change in PHYSICAL state of the substance. ( 2) Change in colour observed in the substance. (3) Evolution of a GAS appears during the reaction. ( 4) Change in TEMPERATURE of the reaction mixture during the reaction. |
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| 204. |
Which one of the following is an oxide of an alkali metal? |
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Answer» `Na_2O` |
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| 205. |
Which of the following statement is not correct about the characterstics of cathode rays |
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Answer» They start from the CATHODE and move TOWARDS the anode |
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| 206. |
While diluting and acid , why is it recommended that the acid should be added to water and not water to the acid ? |
| Answer» Solution :Dilution of CONCENTRATED acid with WATER is a highly exothermicprocess. If water is added int acid, the heat produced is so large that solution may splash out and the beaker in which it is carried out may BREAK due to EXCESSIVE heating . Hence , dilution is done by adding acid into water. | |
| 207. |
When is deliquescence is maximum. |
| Answer» SOLUTION :1. The TEMPERATURE is low 2. The ATMOSPHERE is humid | |
| 208. |
Write the next homologue of each of the following: (i) C_(2)H_(4) (ii) C_(4)H_(6) |
| Answer» Solution :`C_(3)H_(6)`- PROPENE (ii) `C_(5)H_(8)`-Pentyne | |
| 209. |
Write the balanced chemical equation for the following chemical reactions : Sodium + water to sodium hydroxide and hydrogen. |
| Answer» SOLUTION :`2Na+2H_(2)O to 2NaOH+H_(2)`. | |
| 210. |
What is meant by displacement reaction ? Give examples. |
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Answer» Solution : CHEMICAL reaction in which more reactive ELEMENT displaces the less reactive element from its compound (solution) is called displacement reaction. Examples : (1)`Zn(s)+2AgNO_(3)(aq) to Zn(NO_(3))_(2)(aq)+2Ag(s)` (2) `Fe(s)+ CuSO_(4)(aq) to FeSO_(4)(aq)+Cu(s)` (3) `Zn(s)+CuSO_(4)(aq) to ZnSO_(4)+Cu(s)` (4) `Pb(s)+ CuCl_(2)(aq) to PbCl_(2)(aq)+ Cu(s)` Here, Zn, Fe and Pb are more reactive than AG and Cu. |
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| 211. |
Which metals do not corrode easily ? |
| Answer» SOLUTION :Metals which have LOW REACTIVITY such as silver, GOLD do not corrode EASILY. | |
| 212. |
The smell of sulphur dioxide is |
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Answer» LIKE that of BURNING sulphur |
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| 213. |
Which by-product of chlor-alkali process is used for manufacture of bleaching powder ? |
| Answer» SOLUTION :CHLORINE. | |
| 214. |
What do we mean when we say that a substance has gone rancid ? |
| Answer» SOLUTION :It MEANS that the smell and TASTE of the SUBSTANCE have changed. | |
| 215. |
When iron reacts with dilute Hydrochloric acid the liberated gas is |
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Answer» HYDROGEN |
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| 216. |
Write the balanced chemical equation and identify the type of reaction : Potassium bromide(aq) + Barium iodide(aq) to Potassium iodide(aq) + Barium bromide(s) |
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Answer» SOLUTION :`2KBr(AQ) + BaI_(2)(aq) to 2KI(aq) +BaBr_(2)` Given REACTION is a double displacement reaction. |
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| 217. |
What are the uses of copper ? |
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Answer» SOLUTION : (i) Copper is used in manufacturing electric cables and other electric appliances. (II) Copper is used for making utensils , containers , calorimeters and coins . (iii) Copper is used in electroplating. (iv) Copper is ALLOYED with GOLD and silver for making coins and JEWELS . |
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| 218. |
Whichof thefollowingcontainsthe largestnumberof molecules ? |
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Answer» `0.2 molH_(2) ` `2 gm ` of `H_(2) =6.023xx 10 ^(23)` `8 gmof H_(2)=6.023xx 10 ^(23)xx4` ` = 24.092xx 10 ^(23) ` MOLECULES |
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| 219. |
Vinod and Pramod are the best friends. Both study in class X in different schools. Vinod has been running arround in various Government offices for the last one month to get sanction for PNG connection for his home. Due to his efforts Vinod's family has just got a PNG connection in which cooking gas is supplied through pipes. On the other hand, Pamod's family has an LPG connection in which cooking gas is supplied in cylinders. One day Vinod and Pramod were discussingPNG and LPG. Pramod said that PNG is a cooking gas and LPG is alos a cooking gas, therefore their chemical composition is exactly the same. Vinod, however, did not agree with Pramod. Vinod then explained the difference betwen PNG and LPG to Pramod, and also told him the advantage of having a PNG connection. (a) What is the full form of PNG? Name the major component of PNG. (b) What isthe main advantage of having a PNG connection in the home over the LPG connection? (c) What is the difference betwen PNG and CNG? (d) Write the full form of LPG Namd the major component of LPG. (e) The major component of LPG exists intwo forms. Name these two forms. What special name is given to these two forms in organic chemistry? (f) What values are displayed by Vinod in this episode? |
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Answer» SOLUTION :(a) The full form of PNG is Piped Natural Gas. The MAJOR component of PNG is methane `(CH_(4))`. (b) PNG connection provides an uninterrupted and continuous supply of cooking gas to the home through pipes (just like water supply). In LPG connection, however, cooking gas is SUPPLIED to home in cylinders which are to be booked prediodically. And late suply of LPG cylinder may create problem for the household. (c) PNG is piped natural gs whereas CNG is compressed natural gas. Chemically PNG and CNG are just the same. The difference lies in the way thery are supplied and used. PNG is the natural gas which is supplied to the homes through a network of pipes to be used as cooking gas. On the other hand CNG is natural gas which is compressed and filled in cylinders to be used as fuel in motor vehicles (such as cars autos, buses, and trucks etc). (d) The full formof LPG is Liquefied Petroleum Gas. The major component of LPG is butane `(C_(4)H_(10))`. (e) Butane `(C_(4)H_(10))` is present inLPG cylinders in two forms CALLED normal -butane (n-butane) and iso-butane. These two forms of butane are called isomers of butane. They have the same molecular formula but different structures. (f) The various valuesdisplayed by Vinod in this EPISODE are (i) Awareness (that PNGis available as cooking gas in their area ) (ii) Intiave and dreive (to get a PNG connection) (ii) Desire to make life of his family more comfortable (by removing the tension of getting LPG cylinders ) and (iv) Knowledge of the composition of PNG and LPG. |
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| 220. |
Which element has (a) two shells, both of which are completely filled with electrons ? (b) the electronic configuration 2, 8, 2 ? (c) a total of three shells, with four electrons in its valence shell ? (d) a total of two shells, with three electrons in its valence shell ? (e) twice as many electrons in its second shell as in its first shell ? |
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Answer» Solution :Neon (2, 8) (b) MAGNESIUM (2, 8, 2) (c) Silicon (2, 8, 4) (d) Boron (2, 3) (E) CARBON (2, 4) |
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| 221. |
Which of the following metal is most reactive ? |
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Answer» SODIUM |
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| 222. |
When do you get a blue flame? |
| Answer» SOLUTION :When the HOLES of the bunsen burner are opened, enough supply of oxygen-rich air is available, hence, complete COMBUSTION of hydrocarbon takes PLACE and blue flame is formed. | |
| 223. |
Which of the following is (are) ionic compound (s) ? |
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Answer» `KCl` |
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| 224. |
Write the balanced equation for the chemical reactions : Barium chloride + Aluminium sulphate to Barium sulphate + Aluminium chloride |
| Answer» Solution :`3BaCl_(2)(AQ)+ Al_(2)(SO_(4))(aq) to 3BaSO_(4)(s)+2AlCl_(3)(aq)` | |
| 225. |
When an iron rod is dipped into a solution of copper sulphate, copper is displaced. This is because |
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Answer» iron is more electropositive than copper |
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| 226. |
Write the balanced chemical equation for the following reactions : (i) Phosphorus burns in presence of chlorine to form phosphorur pentachloride. Burning of natural gas (iii) The process of resporation |
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Answer» Solution :Chemical equations (i) `5P(s)+10Cl_(2)(g)to4PCl_(5)(s)` (ii) `CH_(4)(g)+2O_(2)(g)toCO_(2)(g)+H_(2)O(l)+"Heat"` (iii) `C_(6)H_(12)O_(6)(aq)+6O_(2)(aq)to6CO_(2)(g)+6H_(2)O+"Heat"`. |
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| 227. |
Which electronic configuration corresponds to an alkali metal?2, 22, 8,22, 8,12,8,8 |
| Answer» SOLUTION :2, 8,1 | |
| 228. |
Water gas is a mixture of |
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Answer» CO and `N_(2)` |
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| 229. |
The standard electrode potentials of four metals A, B, C and D are given below. Based on these values, arrange them in the descending order of ease of deposition of metals from their salt solutions when subjected to electrolysis under standard conditions. (1) rarr - 0.9V (2) rarr -2.71V (3) rarr 0.77V (4) rarr 0.8V |
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Answer» Solution :dcab `d RARR 0.8 V` `C rarr 0.77 V` `b rarr 2.71 V` `a rarr 0.9 V` |
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| 230. |
Write the reactions between methane and chlorine in the presence of diffused sunlight. |
| Answer» Solution :`CH_4 UNDERSET(-HCI)OVERSET(Cl_2) toCH_3 Clunderset(-HCl)overset(Cl_2)toCH_2 Clunderset(-HCl)overset(Cl_2)toCHCl_3underset(-HCl) overset(Cl_2) TOC Cl_4` | |
| 231. |
Which electronic configuration corresponds to an alkali metal? |
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Answer» a)2, 2 |
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| 232. |
You are given samples of three metals : Sodium, magnesium and copper. Suggest any two activities to arrange them in order to their decreasing reactivity. |
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Answer» Solution :(i) Different METALS react with oxygen at different rates. E.g., Sodium (Na) and potassium (K) catch fire, if left in open. Hence, these are the most reactive metals. To prevent accidental fires, these metals are kept immersed in kerosene oil. Magnesium burns in air only by heating. So, it is LESS reactive than sodium and potassium. Copper (Cu) does not burn on heating but blister copper burns. Hence the order of reactivity of these metals with oxygen is : `Na GT Mg gt Cu`. (ii) Metals react with water to produce a METAL oxide and hydrogen GAS. Sodium (Na) and potassium (K) react violently with cold water. So the reaction is violent and exothermic. Magnesium (mg) does not react with cold water. It reacts with hot water. Metals like lead, copper, silver do not react with water at all. The reactivity series of metals towards water is : `Na gt Mg gt Cu`. |
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| 233. |
Translate the following statement into chemical equations and then balance the equations: (i) Phosphorus burns in oxygen to give phosphorus pentoxide. (ii) Aluminium metal replaces iron from ferric oxide, Fe_(2)O_(3), giving aluminium oxide and iron. (iii) Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide. (iv) Barium chloride reacts with zinc sulphate to give chloride and barium sulphate. |
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Answer» <P> Solution :(i) `P_(4)+5O_(2)rarr2P_(2)O_(5)`(ii) `2Al+Fe_(2)O_(3)rarrAl_(2)O_(3)+2Fe` (iii) `CS_(2)+3O_(2)rarrCO_(2)+2SO_(2)` (iv) `BaCl_(2)+ZnSO_(4)rarrZnCl_(2)+BaSO_(4)` |
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| 234. |
Which of the following are unsaturated compounds ? |
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Answer» Ethene, ethyne, PROPENE, proyne |
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| 235. |
Which of the following acid is also known as battery acid that is used in car batteries? |
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Answer» `H_2 SO_4` |
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| 236. |
Two solutions P and Q have pH values of 6 and 2 respectively, which is a stronger acid ? |
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Answer» P |
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| 237. |
To which group of the modern periodic table do alkaline earth metals belong? |
| Answer» SOLUTION :GROUP 2 | |
| 238. |
What is the general formula of alcohols ? Write its functional group. |
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Answer» Solution :GENERAL FORMULA : `C_(N)H_(2n+1)-OH` functional group : - OH |
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| 239. |
Whichof the followingreactionsis notfeasible? |
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Answer» `Zn +CuSO_(4)toZnSO_4 +Cu` |
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| 240. |
Write the balanced chemical equation for each of the following. Quicklime reacts with water releasing a large amount of heat. |
| Answer» SOLUTION :`CaO(s)+H_(2)O(l)TOCA(OH)_(2)(s)+"Energy"`. | |
| 241. |
Which of the following reactions is not correct according to the law of conservation of mass? |
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Answer» `2Mg+O_(2)to2MgO` |
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| 242. |
What is hydrogenation? What is its industrial application ? |
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Answer» SOLUTION :A reaction in which unsaturated hydrocarbons add hydrogen in the PRESENCE of catalysts such as nickel or palladium to form saturated hydrocarbons is known as hydrogenation reaction. Industrial APPLICATION : It is used to CONVERT vegetable oil into vegetable GHEE. 
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| 243. |
There is a sharp decrease in the ionisation energies from boron to aluminium but it is almost the same from aluminium to gallium. Justify. |
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Answer» Solution :Among IIIA group elements, boron has the highest ionisation POTENTIAL due to smaller size. The SHARP decrease in ionisationenergy from boron to aluminium is due to increase in atomic radius. The atomic radius INCREASES due to decrease in effective NUCLEAR charge. In gallium contraction in atomic size is significant due to the presence of completely filled d-electrons in the penultimate shell. Thus. The effective nuclear charge increases. Hence, both aluminium and gallium have almost equal ionisation energy values. |
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| 244. |
When an alpha-particle is emitted |
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Answer» element MOVES 2 places to the RIGHT in the PERIODIC table |
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| 245. |
Translate the following statements into chemical equations and then balance them. (a) Hydrogen gas combines with nitrogen to form ammonia. (b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (c ) Barium chloride reacts wtih aluminium chloride precipitate of barium sulphate. (d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas. |
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Answer» Solution :(a) `N_(2)(g)+3H_(2)(g)rarr2NH_(3)(g)` (b) `2H_(2)S(g)+3O_(2)(g)rarr2H_(2)O(l)+2SO_(2)(g)` (C ) `3BaCl_(2)+Al_(2)(SO_(4))_(3)rarr2AlCl_(3)+3BaSO_(4)darr` (d) `2K(s)+2H_(2)O(l)rarr2KOH(aq)+H_(2)(g)` |
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| 246. |
What is called the insoluble substance formed during the chemical reaction ? |
| Answer» SOLUTION :PRECIPITATE | |
| 247. |
Which of the following are used as anaesthetics? |
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Answer» CARBOXYLIC ACIDS |
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| 248. |
Which of the following k_(c) values corresponds to the maximum yield of the product ? |
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Answer» `9.2 XX 10^(2)` |
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| 249. |
The solution of a substance in water is slippery. It combines with an acid to produce a salt. The subtance is |
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Answer» an acid |
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| 250. |
What is an elecric current? Write its SI unit. |
| Answer» SOLUTION :The rate of flow of CHARGES through a conductor is CALLED an electric CURRENT. Its SI unit is AMPERE (A) . | |