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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.
| 8101. |
Aim: To study electrolysis of water. Activity: Take a plastic mug. Drill two holes at the base of the mug. Fix two rubber corks in it, as shown in the figure 1.6. Arrange the test tubes in inverted position such that carbon electrodes remains in it as shown in the figure. Add water in a mug such that electrodes are immersed. Add a few drops of dilute sulphuric acid to water. Connect electrodes to a 6 volt battery. Now, switch on the current and leave the apparatus undisturbed for some time. Which gas is evolved at cathode during electrolysis of water ? |
| Answer» SOLUTION :HYDROGEN gas is evolved at CATHODE during ELECROLYSIS of water. | |
| 8102. |
Aim: To study electrolysis of water. Activity: Take a plastic mug. Drill two holes at the base of the mug. Fix two rubber corks in it, as shown in the figure 1.6. Arrange the test tubes in inverted position such that carbon electrodes remains in it as shown in the figure. Add water in a mug such that electrodes are immersed. Add a few drops of dilute sulphuric acid to water. Connect electrodes to a 6 volt battery. Now, switch on the current and leave the apparatus undisturbed for some time. State the chemical equation of reaction of electrolysis of water. |
| Answer» SOLUTION :`H_(2)O(I) overset("ELECTROLYSIS")to 2H_(2)(G)+O_(2)(g)` | |
| 8103. |
Aim: To study double displacement reaction between barium chloride and sodium sulphate.Activity: Take about 3 mL of sodium sulphate solution in a test tube. In another test tube, take about 3 mL of barium chloride solution. Mix the two solutions as shown in the figure. Write a balanced chemical equation for the reaction between barium chloride and sodium sulphate. |
| Answer» SOLUTION :`BaCl_(2)(aq)+ Na_(2)SO_(4)(aq) to BaSO_(4)(s)+ 2NaCl(aq)` | |
| 8104. |
Aim: To study double displacement reaction between barium chloride and sodium sulphate.Activity: Take about 3 mL of sodium sulphate solution in a test tube. In another test tube, take about 3 mL of barium chloride solution. Mix the two solutions as shown in the figure. What type of chemical reaction takes place between barium chloride and sodium sulphate ? |
| Answer» Solution :A CHEMICAL reaction TAKING place between barium chloride and sodium SULPHATE is a double DISPLACEMENT reaction. | |
| 8105. |
Aim: To study double displacement reaction between barium chloride and sodium sulphate.Activity: Take about 3 mL of sodium sulphate solution in a test tube. In another test tube, take about 3 mL of barium chloride solution. Mix the two solutions as shown in the figure. Which precipitate is obtained by mixing the solution of sodium sulphate and barium chloride ? Mention its colour. |
| Answer» SOLUTION :When solutions of sodium sulphate and BARIUM chloride are mixed, a precipitate of barium sulphate (`BaSO_(4)`) is FORMED, which is WHITE in colour. | |
| 8106. |
Aim: To study double displacement reaction between barium chloride and sodium sulphate.Activity: Take about 3 mL of sodium sulphate solution in a test tube. In another test tube, take about 3 mL of barium chloride solution. Mix the two solutions as shown in the figure. What is the colour of sodium sulphate and barium chloride solutions ? |
| Answer» SOLUTION :Sodium SULPHATE and barium CHLORIDE are colourless SOLUTIONS. | |
| 8107. |
Ahmad took a magnesium ribbon and burned it on a flame. The white powder formed was taken in a test tube and water was added to it. He then tested the solution formed with red and blue litmus paper. What change was seen ? Why ? |
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Answer» SOLUTION : RED litmus paper turned blue. Blue litmus paper remained blue. This is because the Magnesium RIBBON on burning in air forms the WHITE Magnesium oxide, MgO, when dissolved in water, it forms magnesium hydroxide, which is basic in nature. `2Mg+O to 2MgO` `MgO+H_(2)O to Mg(OH)_(2)(aq)+H_(2)(G)` |
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| 8108. |
Agricultural scientists have suggested to add a certain amount of lime powder to an agricultural field. What may be the reason for this ? Explain. |
| Answer» SOLUTION :If the SOIL is acidic in NATURE, the above treatment is DONE to neutralize the soil. | |
| 8109. |
{:(AgNO_(3)(aq)+NaCl(aq)toAgCl(s)darr+NaNO_(3)(aq)),(""FeS+H_(2)SO_(4)toFeSO_(4)+H_(2)Suarr):} Consider the above mentioned two chemical equations with two different kinds of arrows (uarr) and (darr) along with products. What do these two different arrows indicate ? |
| Answer» Solution :The upward ARROW `(uarr)` indicates that the product is a gas while the DOWNWARD arrow `(uarr)` indicates that the product is insoluble and appears as precipitate. | |
| 8110. |
AgNO_(3)(aq)+NaCl(aq) to AgCl(s) darr+NaNO_(3)(aq) FeS(s)+H_(2)SO_(4)(aq) to FeSO_(4)+ H_(2)Suarr |
| Answer» SOLUTION :`DARR` INDICATE the formation of INSOLUBLE SUBSTANCE (precipitate) while `darr` represent the evolution of gas. | |
| 8111. |
AgNO_(3)+NaCl to AgCldarr+NaNO_(3) FeS+H_(2)SO_(4)toFeSO_(4)+H_(2)Suarr What do the upward and downward arrow marks indicate in the above chemical equations ? |
| Answer» Solution :`uarr` Upward ARROW mark indicates that gas is evolved and `DARR` downward arrow mark indicates that an insoluble PRECIPITATE (COMPOUND) is formed. | |
| 8112. |
AgNO_(3) is soluble salt of silver, but it is preferable to use (NaCN + AgCN) as an electrolyte for silver plating. Give a reason in support of your answer. |
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Answer» SOLUTION :(i) Formation of complex (ii) The characteristic of salt RESPONSIBLE for electrolysis. (iii) COMPARISON of strengths of the two electrolytes given. (iv) Effect of ADDITION of NaCl to a solution of AGCN (v) Purpose of electroplating (vi) Effect of addition of NaCN on the quality of electroplating. |
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| 8113. |
Ag_(2)S + 4NaCN hArr 2Na[Ag(CN)_(2)]+ Na_(2)S . Oxidation of sodium sulphide formed is the important step in the extration of silver from its ore . Justify. |
| Answer» Solution :In the extraction of silver from its ore, of the IMPORTANT steps is the FORMATION of sodium argentocyanide and sodium sulphide that is a REVERSIBLE reaction. To prevent the reversibility of the reaction sodium sulphide should be subjected to oxidation . because accordingto LE Chatelier's principle , with the removal of one of the products , the reaction SHIFTS in the forward direction. | |
| 8114. |
After usage for a certain period, a cooking gas cylinder gas cylinder was considered to be empty, as no gas was coming out of it. Is the cylinder empty in its true sense? Explain what happens if the cylinder is kept in hot water or shaken vigorously. Explain byapplying kinetic molecular theory. |
| Answer» Solution :No, it is not empty in its true sense. In a cooking gas CYLINDER, THEGAS was initially at a high PRESSURE. As thegas was drawn out FORM thecylinder, theamount of gas in thecylinder decreases, thereby reducing thepressure inside the cylinder. Thegaswill come out of thecylinder as long asthepressure of the gas inside the cylinder is more than theatmospheircpressure. When it is keptin hot water or shaken vigorously, kinetic energy of gas MOLECULES increases and the number of collisions increases. Thus, pressure increases and gas comes out of thecylinder. | |
| 8115. |
After drinking excess of cold drink, a person suffers from acidity. Explain. |
| Answer» Solution :COLD drinks contain carbon dioxide gas dissolved in them under pressure. Some amount of the gas escapes when a bottle of cold drink is opened while a portion of it REMAINS dissolved. Carbon dioxide dissolved in water forms a weak acid, i.e., CARBONIC acid. Consumption of excess of cold drink causes accumulation of carbonic acid in the stomach which is responsible for the DEVELOPMENT of ACIDITY. | |
| 8117. |
Aeratedsoftdrinkscontain dissolved______ina popbottle . |
| Answer» SOLUTION :CARBONDIOXIDE | |
| 8118. |
Addition of water to ethane yields : |
| Answer» Answer :C | |
| 8119. |
Addition of cryolite and fluorspar to alumina produces a dangerous by-product'. Comment. |
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Answer» Solution :(i) Common element present in cryolite and fluorspar. (II) Ions present in cryolite and fluorpar. (iii) Products OBTAINED at the ELECTRODES on COMPLETE electrolysis. (IV) Nature of the products. |
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| 8121. |
……………….acts as food for yeast during the fermentation of molasses. |
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Answer» AMMONIUM sulphate |
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| 8122. |
Action of heat on ferrous sulphate crystals is an example of decomposition reaction . |
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Answer» |
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| 8124. |
Actinide Series |
| Answer» SOLUTION :The SERIES of Fourteen ELEMENTS from Thorium [Th (90)] to LAWRENCIUM [Lr (103)] is called ACTINIDE Series. | |
| 8127. |
Acids present in plants and animals are………….. And the acids in rocks and minerals are……….. |
| Answer» SOLUTION :ORGANIC ACID,INORGANIC acid | |
| 8130. |
Acid solution in water conducts electricity. |
| Answer» Solution :TRUE - This is became ACID solution contains `H^+` ions ALONGWITH an ANION. | |
| 8132. |
Acid rain has pH : |
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Answer» More than 5.6 |
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| 8135. |
Acid + Base to Salt + Water. This reaction is known as |
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Answer» NEUTRALISATION reaction |
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| 8137. |
Acetic acid reacts with ethyl alcohol in the presence of concentrated sulphuric acid producing a sweet smelling compound. For the reaction : (i) name the main product (ii) write chemical equation. |
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Answer» Solution :(i) Main product is ethyl ACETATE (an ester) (ii) Chemical equation is : `underste("ACETIC acid")(CH_(3)COOH) + underset("Ethyl alcohol")(C_(2)H_(5)OH) OVERSET(Conc. H_(2)SO_(4), Delta)rarr underset("Ethyl acetate")(CH_(3)COOC_(2)H_(5)) + H_(2)O` |
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| 8139. |
Acetic acid is a weak because |
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Answer» its AQUEOUS solutioni is acidic |
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| 8140. |
Acetic acid is |
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Answer» red |
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| 8141. |
Acetic acid contains four hydrogen atoms in each molecule. Explain why it is not a tetrabasic acid ? |
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Answer» Solution :(i) REPLACEABLE hydrogens in acetic ACID (ii) structure and bonding in acetic acid (iii) comparison of the position of the hydrogen ATOMS present in the molecule of acetic acid (IV) relation between the position of hydrogen atom and the effect of strong alkali on it |
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| 8142. |
Account for the very stable nitrogen atotn in contrast to its neighbouring carbon and oxygen atoms. |
| Answer» Solution :Nitrogen has half-FILLED configuration `2s^2 2p^3`, while carbon `2s^2 2p^2` and oxygen `2s^2 2p^4` have no half- filled configurations. The ATOMS with half-filled congurations are exceptionally STABLE. This is due to the symmetry in the arrangement of the electrons ill the orbitals and mutual exchange of energy among the PARALLEL spins of electrons that lowers the energy of system. Hence, it BECOMES more stable | |
| 8143. |
Account for the variation of acidic character with increases in the oxidation state of central atom |
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Answer» SOLUTION :(i) effect of electronegative atom on the `O -H` bond strength (ii) effect of oxidation STATE of the central atom on the position of electron CLOUD present between oxygen atom and the central atom (iii) RELATION between the position of the above electron cloud and the charge separation between hydrogen and oxygen atom of the hydroxylradical attached to the central atom (IV) relation between the above charge separation and ease of formation of hydrogen ion (v) relation between ease of formation of hydrogen ion with the acidic character of the respective acids |
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| 8144. |
Account for the following: (i) State the relation between hydrogen ion concentration of an aqueous solution and its pH. (ii) An aqueous solution has a pH value of 7.0 Is this solution acidic, basic or neutral. (iii) Which has a higher pH value, 1M HCl or 1M NaOH solutions? (iv) Tooth enamel is one of the hardest substances in our body. How does it undergo damange due to eating chocolates and sweets? What should we do to prevent it? |
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Answer» Solution :(i) IF `H^+` ion CONCENTRATION is more,pH will be less and vice VERSA or pH of a solution is inversely proportional to `H^+` ion concentration or pH=- log `(H^+)` (ii) This solution is neutral. (ii) 1M NaOH solution. (iv) When the PH in the mouth is below 5.5 BACTERIA present in the mouth produce acids by degradation of SUGAR and corrode the tooth enamel. It can be prevented by using tooth pastes which are GENERALLY basic in nature. |
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| 8145. |
Account for the following: Elements of group 18 are zerovalent. |
| Answer» SOLUTION :Elements of group 18 have completely filled VALENCE shell and hence SHOW no tendency to gain or lose ELECTRONS. Hence, they are ZEROVALENT. | |
| 8146. |
Account for the following: Elements of group 17 are monovalent. |
| Answer» Solution :Group 17 elements have 7 VALENCE ELECTRONS. By gaining one electron, they attain the noble GAS CONFIGURATION. Since valency is defined as the NUMBER of electrons required to gain noble gas configuration, valency of group 17 elements is one, i.e., they are monovalent. | |
| 8147. |
Account for the following : (a) White silver chloride turns grey in sunlight. (b) Brown coloured copper powder on heating in air turns into black coloured substance. |
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Answer» SOLUTION :(a) Silver CHLORIDE TURNS grey on exposure to sunlight because of the following reaction : `2AgCl OVERSET("Sunlight")(to)underset("(grey)")underset("Metallic silver")(2Ag+Cl_(2))` (b) Oxidation of copper powder takes PLACE. The oxide formed has a black colour. `underset("Brown")(2Cu)+O_(2)overset("Heat")(to)underset("Black")(2CuO)` |
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| 8148. |
Account foe the following : (a) Dry HCl gas does not change the colour of dry blue litmus paper. (b) Antacid tablets are used by a person suffering from stomach pain. |
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| 8149. |
According to the Newlands law of octaves, every eighth element had properties similar to that of the first element. |
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Answer» |
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| 8150. |
According to second law of thermodynamics |
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Answer» `DELTA S_("TOTAL") = +ve` |
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