InterviewSolution
Saved Bookmarks
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.
| 251. |
Class 7 Science MCQ Question of Acids, Bases and Salts with Answers? |
|
Answer» Students can get here Class 7 Science MCQ Questions of Acids, Bases and Salts with Answers based on NCERT Text book for Class 7. Science Class 7 MCQ Questions of Acids, Bases and Salts are very helpful to score high marks in board exams. MCQ Questions for Class 10 Science with Answers was Prepared Based on Latest Exam Pattern. Know your preparation level on MCQ Questions with Answers. Here we have covered Important Questions on Acids, Bases and Salts for Class 7 Science. If you practiced properly. You also get idea about the type of questions and method to answer in your Class 7 examinations. Students can solve Class 10 Science Acids Bases and Salts Multiple Choice Questions with Answers to know their preparation level. You can also verify your answers from our provided International Business 1 Class 11 MCQ Questions with Answers. Practice MCQ Questions for Class 7 Science 1. An oxide is acidic and has a pungent odour. It could be (a) sulphur dioxide 2. Out of these gases which one is used in fire extinguishers (a) CO2 3. The correct way of making a solution of acid in water is to (a) add water to acid 4. Products of a neutralisation reaction are always: (a) an acid and a base 5. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed. (a) Yellow in both acid and base 6. Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are: (a) red and blue 7. When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil? (a) Organic matter 8. Which of the following set of substances contain acids? (a) Grapes, lime water 9. On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution? (a) Basic 10. Which of the following is an acid-base indicator? (a) Vinegar 11. Which of the following is not a indicator? (a) Phenolphthalein 12. When CO2 gas is passed through lime water, it turns milky. Which of the following compounds is responsible for this milkiness ? (a) Calcium oxide 13. The reaction in which an acid react with a base to form salt and water is called as (a) Addition reaction 14. Which of the following ion is responsible for the acidic nature of hydrochloric acid ? (a) Hydrogen ion 15. Acid present in soured curd is (a) Lactic acid 16. Distilled water is: (a) acidic 17. Ammonia that turns red litmus blue is: (a) acidic 18. An antacid tablet is given to a person when he suffers from: (a) obesity 19. Ant’s bite injects: (a) acetic acid 20. Litmus is extracted from (a) curd 21.Acid used in eye wash is (a) carbonic acid 22. Magnesium hydroxide is found in: (a) soap 23. Calcium hydroxide is found in (a) window cleaner 24. Acid present in cold drinks (soft drinks) is (a) Carbonic acid 25. Which of the following is a strong Base? (a) Copper hydroxide Answer: 1. Answer: (d) nitrogen dioxide Explanation: Nitrogen dioxide is non- metallic oxide hence it is acidic in nature and it has a pungent odour. 2. Answer: (a) CO2 Explanation: Three types of extinguishing agents are typically used—carbon dioxide, dry chemical, and foam water for fires involving flammable liquids, greases, and oils. Carbon dioxide is a compressed gas agent that prevents combustion by displacing the oxygen in the air surrounding the fire. 3. Answer: (b) add acid to water Explanation:When we add water to acid, it releases some amount of energy. We can feel this energy by touching the surface of the test tube. Sometimes, released heat is too huge, because of this glasses of test tube may break down and acid can split over. So, in practice, you have to take an excessive amount of water and mix acid drop by drop. In this way, heat generated can be cooled down by this water and mistakes can be prevented. 4. Answer: (c) a salt and water Explanation:The product of a neutralisation reaction is salt and water. For example, hydrochloric acid reacts with sodium hydroxide to form sodium chloride salt and water. 5. Answer: (b) Yellow in acid and red in base Explanation: Turmeric compound is a naturally occurring yellow color compound. It is an acid-base indicator, it remains yellow when acidic or neutral solutions are added to it. 6. Answer: (d) colourless and pink Explanation: Phenolphthalein is a synthetic indicator and is weakly acidic in nature. When it is added to an acidic solution, it turns colourless. In the basic solution, it appears pink in colour.Phenolphthalein is colourless in acidic solution and pink in basic solution. 7. Answer: (a) Organic matter Explanation: To improve quality and reduce the basic nature of the soil, the organic matter must be added to the soil. Organic matter releases acids that can neutralize the base of the soil and hence the quality of soil can be improved. 8. Answer: (d) Curd, vinegar Explanation: Curd contains lactic acid and vinegar contains acetic acid. Lime water, soap and milk of magnesia are basic substances and grapes contains tartaric acid. 9. Answer: (c) Either acidic or neutral Explanation: Phenolphthalein gives pink colour in basic solution. It remains colourless in acidic or neutral solution.Phenolphthalein only gives colour in basic medium. 10. Answer: (c) Turmeric Explanation: Turmeric compound is a naturally occurring yellow colour compound. It is an acid-base indicator, turmeric compound remains yellow when acid or neutral solutions are added to it. 11. Answer: (d) Methyl chloride Explanation: Methyl chloride cannot act as an indicator because it does not show any colour change in acidic or basic medium whereas methyl orange, phenolphthalein and turmeric are well-known indicators. 12. Answer: (d) Calcium carbonate Explanation: Lime water is calcium hydroxide and when carbon dioxide is passed it reacts with calcium hydroxide to form calcium carbonate which turns lime water milky. 13. Answer: (c) Neutralisation reaction Explanation: The reaction between acid and base produces salt and water, which is the example of neutralization reaction. 14. Answer: (a) Hydrogen ion Explanation: The presence of hydrogen ions |H+| imparts acidic nature to HCl. 15. Answer: (a) Lactic acid Explanation: Lactic Acid or milk acid is an organic acid with chemical formula C3H6O3. When milk sugar or lactose undergoes fermentation, the product obtained is lactic acid. It is found in cottage cheese, leban, sour milk, yogurt, and Koumiss. 16. Answer: (c) neutral Explanation: Distilled water is neutral in character, i.e. it is neither acidic nor basic. Neutral nature of distilled water can be verified by the use of blue and red litmus paper. 17. Answer: (b) basic Explanation: Ammonia turns red litmus to blue so it is basic in nature. 18. Answer: (b) acidity Explanation: We take an antacid such as milk of magnesia to neutalises the excessive acid released in stomach. 19. Answer: (b) formic acid Explanation: Formic acid, a component of ant venom uncommon in bee or wasp stings, is derived from the superfamily name Formicidae. 20. Answer: (c) lichens Explanation: Litmus, mixture of coloured organic compounds obtained from several species of lichens that grow in the Netherlands, particularly Lecanora tartarea and Roccella tinctorum. 21.Answer: (d) boric acid Explanation: Boric acid is often an ingredient in eye wash products. It's predominantly used as a mild antiseptic and to maintain the pH of the eye wash solution. 22. Answer: (c) milk of magnesia Explanation: Magnesium hydroxide is an ingredient in OTC products, such as Milk of Magnesia. It also draws water into the intestines to help soften stool and encourage a bowel movement. 23. Answer: (b) lime water Explanation: solutions of calcium hydroxide in water is known as lime water. Hence, Calcium Hydroxide {Ca(OH)2} is found in lime water. 24. Answer: (a) Carbonic acid Explanation: Carbonic acid is added to soft drinks to make it fizzy. When the bottle is opened, the pressure decreases and the carbonic acid changes into carbon dioxide and water making it fizzy. 25. Answer: (b) Sodium hydroxide Explanation: Sodium hydroxide is a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Sodium hydroxide is completely ionic, containing sodium ions and hydroxide ions. Click here for Practice MCQ Questions for Acids, Bases and Salts Class 7 |
|
| 252. |
State differences between acids and bases. |
|
Answer» Acids:
Bases:
|
|
| 253. |
State the differences.Acids and bases |
||||
Answer»
|
|||||
| 254. |
Write three differences between acids and bases. |
||||||||
|
Answer» Difference between acids and bases:
|
|||||||||
| 255. |
When a solution is added to a cloth strip treated with onion extract, then the smell of onion cannot be detected. State whether the given solution contains an acid or a base. |
|
Answer» The given solution contains an acid or a base- Base. |
|
| 256. |
State differences between acids and bases. |
||||||||||||
Answer»
|
|||||||||||||
| 257. |
While demonstrating acid base reactions, Ms. Prabha, a science teacher added sodium oxide to HCI until it was in excess. Which of the following graphs correctly represents the change in pH? |
|
Answer» Correct option (A) Explanation: pH of HCI is below is 7. When Na2O is added, pH increases till neutralisation point and then further increaSes due to excess of Na2O which is basic. |
|
| 258. |
Ayaan tested the nature of a few common substances with phenolphthalein indicator and summarised the results in the following tableTest tubeColour change with phenolphthalein indicator1Colourless2Pink3Colourless4PinkWhich of the following substances could be present in test tubes 1, 2, 3 and 4? |
|
Answer» Correct option (c) Explanation: Phenolphthalein remains colourless in acidic solution (lemon juice) and neutral solution (common salt solution). ln basic solution (lime water and baking soda), it turns pink. |
|
| 259. |
Few statements regarding the properties of bases are given below. Mark the correct statements? (i) Sodium hydroxide and potassium hydroxide are soluble in water. (ii) Calcium hydroxide and magnesium hydroxide are partially soluble in water. (iii) All metallic hydroxides react with acids to form their respective metallic salts. (iv) Metallic oxides are acidic oxides hence they react with acids to form salts. (A) (i), (ii) and (iv) only (B) (i), (iii) and (iv) only (C) (i), (ii) and (iii) only (D) (ii) and (iii) only |
|
Answer» Correct option (C) (i), (ii) and (iii) only Explanation: Metallic oxides are basic oxides hence, they react with acids to form salts. |
|
| 260. |
Sunil set up an experiment as shown in the figure to test a few solutions which contain hydrogen but are not categorized as acids.Which of the given observations are correct? (i) When a solution of glucose is put, the bulb does not glow. (ii) When a solution of ethanol is put, the bulb does not glow. (iii) When a solution of hydrochloric acid is put, the bulb glows. (iv) When a solution of sodium hydroxide is put, the bulb does not glow.(A) (i), (ii) and (iv) only (B) (i), (ii) and (iii) only (C) (i) and (ii) only (D) (iii) and (iv) only |
|
Answer» Correct option (B) (i), (ii) and (iii) only Explanation: Glucose and ethanol do not conduct electricity while NaOH and HCI conduct electricity as they produce ions in the solution. |
|
| 261. |
Write word equations and then balanced equations for the reaction taking place when :(a) dilute sulphuric acid reacts with zinc granules.(b) dilute hydrochloric acid reacts with magnesium ribbon.(c) dilute sulphuric acid reacts with aluminium powder.(d) dilute hydrochloric acid reacts with iron filings.A. dilute sulphuric acid reacts with zinc granules.B. dilute hydrochloric acid reacts with magnesium ribbon.C. dilute sulphuric acid reacts with aluminium powder.D. dilute hydrochloric acid reacts with iron filings. |
|
Answer» (a) Sulphuric acid + Zinc `to` Zinc sulphate + Hydrogen `H_(2)SO_(4(aq))+Zn_((s)) to ZnSO_(4(aq))+H_(2(g))` (b) Hydrochloric acid + Magnesium `to` Magnesium chloride + Hydrogen `2HCl_((aq)) +(Mg_((s))) to MgCl_(2(aq))+H_(2(aq))` (c) Sulphuric acid + Aluminium `to` Aluminium sulphate + Hydrogen `3H_(2)SO_(4(aq))+2Al_((s)) to Al_(2) (SO_(4))_(3(aq))+3H_(2(g))` (d) Hydrochloric acid + Iron `to` Ferric chloride + Hydrogen `6HCl_((aq))+2Fe_((s)) to 2FeCL_(3(aq))+3H_(2(g))` |
|
| 262. |
Name the salt used for the manufacture of glass. Give its formula. |
| Answer» Sodium carbonate is used for the manufacture of glass. `Na_(2)CO_(3)* 10H_(2)O` | |
| 263. |
Name a natural indicator. |
| Answer» Red cabbage juice is a natural indicator. | |
| 264. |
Which one of the following types of medicines is used for treating indigestion?A. AntibioticB. AnalgesicC. AntacidD. Antiseptic |
| Answer» (c) Antacid is used for treating indigestion. | |
| 265. |
Give the formulae of the following salts. (a) Blue vitriol (b) Green vitriol (c) Potash alum |
| Answer» Blue vitriol `-CuSO_(4)*5H_(2)O`, Green vitriol `-FeSO_(4)*7H_(2)O` Potash alum `-K_(2)SO_(4)*A1_(2)(SO_(4))_(3)*24H_(2)O`. | |
| 266. |
Name of the salt formed by treating calcium oxide solution with nitric acid is ________ .A. calcium nitrateB. calcium nitriteC. calcium hydrogen nitrateD. calcium hydrogen nitrite |
|
Answer» Correct Answer - A Calcium nitrate salt is formed by treating calcium oxide solution with nitric acid. |
|
| 267. |
Why is KOH called caustic potash? |
| Answer» KOH causes causticising action on skin and therefore it is called caustic potash. | |
| 268. |
The salt formed by complete neutralization of calcium hydroxide with sulphuric acid isA. calcium sulphiteB. calcium bisulphateC. calcium sulphateD. calcium bisulphite |
|
Answer» Correct Answer - C `H_(2)SO_(4) + Ca(OH)_(2) rarr CaSO_(4) + 2H_(2)O` Calcium sulphate |
|
| 269. |
Chile salt petre and nitre are respectivelyA. sodium nitrate and potassium nitrateB. potassium nitrate and sodium nitrateC. ferroous sulphate and copper sulphateD. copper sulphate and ferrous sulphate |
|
Answer» Correct Answer - A Chile salt petre and nitre are respectively sodium nitrate and potassium nitrate. |
|
| 270. |
identify the basic radical and acidic radical in sodium nitrate. |
| Answer» In sodium nitrate `Na^(+)` is basic radical and `NO_(3)^(-)` is acidic radical. | |
| 271. |
How is the concentration of hydroxide ions` (OH^(–))` affected when excess base is dissolved in a solution of sodium hydroxide? |
| Answer» The concentration of hydroxide ions` (OH^(−))` would increase when excess base is dissolved in a solution of sodium hydroxide. | |
| 272. |
`{:(,"Column A",,,"Column B"),(A.,"Sodium dihydrogen phosphate",(),a.,"Basic salt"),(B.,"Calcium hydroxy chloride",(),b.,"Gun powder"),(C.,"Nitre",(),c.,"Manufacture of glass"),(D.,"Ammonium carbonate",(),d.,"Acidic salt"),(,,(),e.,"Normal salt"),(,,,f.,"Smelling salt"):}` |
|
Answer» Correct Answer - `A rarr d` `B rarr a` `C rarr b, e` `D rarr f` A `rarr` d Sodium dihydrogen phosphate is an acidic salt. B `rarr` a Calcium hydroxy chloride is a basic salt. C `rarr` b, e Nitre is one of the components present in gunpowder. It is a normal salt. D `rarr` f Ammonium carbonate is called smelling salt. |
|
| 273. |
Name the acid and base from which the following salts are formed. (a) Sodium chloride (b) Potassium sulphate (c) Calcium nitrate |
|
Answer» (i) Sodium chloride Acid - HC1, base - NaOH (ii) Potassium sulphate Acid - `H_(2)SO_(4)`, base - KOH (iii) Calcium nitrate Acid - `HNO_(3)`, base - `Ca(OH)_(2)` |
|
| 274. |
In an attempt to demonstrate electrical conductivity through an electrolyte, the apparatus set up is given. Which among the following statement (s) is (are) correct ? (i) Bulb will not glow because electrolyte is not acidic (ii) Bulb will glow because HCl is strong acid and furnishes ions for conduction. (iii) Bulb will not glow because circuit is incomplete (iv) Bulb will not glow because it depends upon the type of electrolytic solutionA. (i) and (iii)B. (ii) and (iv)C. (ii) onlyD. (iv) only |
|
Answer» Correct Answer - C Bullb will glow because the acid will furnish ions which conduct electricity. Therefore statement (ii) is correct. |
|
| 275. |
Do basic solutions also have `H^(+)(aq)` ions? If yes, then why are these basic? |
| Answer» Yes, basic solution also has` H^(+)(aq)` ions. However, their concentration is less as compared to the concentration of` OH^(-)`ons that makes the solution basic. | |
| 276. |
If a nonmetal forms only two oxides and one oxide on hydrolysis gives an acid, then the non-metal could beA. sulphurB. carbonC. phosphorusD. nitrogen |
|
Answer» Correct Answer - B Carbon forms two oxides. `CO_(2)` on hydrolysis gives carbonic acid and CO is neutral. Carbon is the non-metal. `CO_(2) + H_(2)O rarr H_(2)CO_(3)` |
|
| 277. |
You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic? |
| Answer» A pH value of less than 7 indicates an acidic solution, while greater than 7 indicates a basic solution. Therefore, the solution with pH = 6 is acidic and has more hydrogen ion concentration than the solution of pH = 8 which is basic. | |
| 278. |
Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper . What would be the colour obtained ?A. RedB. YellowC. Yellowish greenD. Blue |
|
Answer» Correct Answer - C Beacue the resulting solution is obtained as a result of neutralisation reaction `HCI+NaOHrarr NacI+H_(2)O` The colour of the neutral solution (with pH=7) obtained is yellowish green. |
|
| 279. |
Define salt hydrolysis. Explain the nature of aqueous solution of `CuSO_(4)`, on the basis of the above phenomenon |
|
Answer» The phenomenon in which a salt on dissolution in water forms a parent acid and a parent alkali resulting in acidic, basic or neutral solution is called salt hydrolysis. It is the most important property of salts. `CuSO_(4)` on hydrolysis produces a strong acid that ionises and a weak base that does not ionsie. This increases the concentration of `H^(+)` ions making the solution acidic with `pH lt 7` ( at `25^(@)C`) `Cu^(+2) + SO_(4)^(-1) + 2H_(2)O rarr Cu(OH)_(2) + 2H^(+) + SO_(4)^(-2)` As cation of the salt reacts with water, it is called cationic hydrolysis |
|
| 280. |
Which among the following factors changes the value of ionic product of water ?A. change in temperatureB. addition of acidC. addition of baseD. addition of either acid and base |
| Answer» Correct Answer - A | |
| 281. |
Which among the following is a hydrated salt?A. MarbleB. Baking sodaC. Green vitriolD. All of these |
|
Answer» Correct Answer - C Marble `rarr CaCO_(3)` Green vitriol `rarr FeSO_(4)*7H_(2)O` Baking Soda `rarr NaHCO_(3)` |
|
| 282. |
________ which is a hydrated salt is used as a fungicide in agriculture. |
|
Answer» Correct Answer - Copper sulphate Blue vitriol `(CuSO_(4)*5H_(2)O)` is used as fungicide in agriculture. |
|
| 283. |
During the preparation of hydrogen chlorides gas on a humid day the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloiride taken in the guard tube is toA. asorb the evolved gasB. moisten the gasC. absorb moisture form the gasD. bsorb CI-ions from the evolved gas |
|
Answer» Correct Answer - C The role of calcium chloride `(CaCI_(2))` is to absorb moisture from the gas. Because calcium chloride is a good dehydrating angen. |
|
| 284. |
In an attempt to demonstrate electrical conductivity through an electrolyte the following apparatus (figure ) set up Which among the following statement(s) is / are correct? (i) Bulb will not glow because electrolyte is not acidic . (ii) Bulb will glow because NaOH is atrong base and furnishes ions for conduction (iii) Bulb will not glow becuse circuit is incomplete. (iv) Bulb will not glow becuse it depends upon the type of electrolytic solution.A. (i) and (iii)B. (ii) abd (iv)C. Only (ii)D. Only (iv) |
|
Answer» Correct Answer - C Bulb will glow because NaOH being sa strong base frunishes `OH^(-) and Na^(+)` ions (which are responsible for electrical conductivity). |
|
| 285. |
`K_(2)SO_(4).Al_(2) (SO_(4))_(3) 24H_(2)O` gives reactions of both `K^(+) and Al^(+3)` ions respectively |
| Answer» Correct Answer - 1 | |
| 286. |
Which of the following solutions has the same concentration of `H^(+)` ions as 0.1 N HCl ?A. 0.1 N `H_(2)SO_(4)`B. 0.3 N `H_(3)PO_(4)`C. 0.2 N `HNO_(3)`D. All of these |
| Answer» Correct Answer - A | |
| 287. |
The spectator ions in the hydrolysis of `(NH_(4))_(2) CO_(3)` areA. `NH_(4)^(+), H^(+), OH^(-)`B. `NH_(4)^(+), CO_(3)^(2-), H^(+), OOH^(-)`C. `CO_(3)^(2-), H^(+), OH^(-)`D. no spectator ions |
| Answer» Correct Answer - D | |
| 288. |
Hydrated sodium sulphate and hydrated copper sulphate are taken in two air tight containers X and Y respectively. When blue coloured `CoCl_(2)` is introduced into the two containers, there is colour change in one container. Identify the container and give reaseons in support of your answer. |
|
Answer» Hydrated sodium sulphate `rarr Na_(2)SO_(4)*10H_(2)O` Hydrated copper sulphater `rarr CuSO_(4)*5H_(2)O` As hydrated sodium sulphate is efflorescent in nature it loses water of crystallization. Blue coloured `CoC1_(2)` present in container "X" absorbs moisture and turns to pink coloured `CoC1_(2)*2H_(2)O` `underset("blue")(CoC1_(2)) overset("moisture")(rarr) underset("pink")(CoC1_(2)*2H_(2)O)` |
|
| 289. |
Which of the following cannot show acidic nature ?A. `H_(2)CO_(3)`B. `CaCO_(3)`C. HClD. `HSO_(4)^(-)` |
| Answer» Correct Answer - B | |
| 290. |
Which of the following gives the correct increasing order of acid strength?A. water `lt` acetic acid `lt` hydrochloric acidB. water `lt` hydrochloric acid `lt` acetic acidC. Acetic acid `lt` water `lt` hydrochloric acidD. Hydrochloric acid `lt` water `lt` acetic acid |
|
Answer» Correct Answer - A Hydrochloic acid is a mineral acid and ionises completely in water that,s why it is a strong aid. Acetic acid is an orgainic acid and ionises only partially in water, hence it is a weak acid. Water has some what neutral nature. Tus , the order of acidity ios water lt acietic acid lt hydrochloirc acid. |
|
| 291. |
If a few drops of a concentrated acid accidentally spill over the hand of a student, what should be done?A. Wash the hand with saline solutionB. Wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonateC. After washing hand with plenty of water, apply solution of sodium hydroxide on the handD. Neutralise the acid with a strong alkali |
|
Answer» Correct Answer - B Wasshing the hand initially with plenty of water gives partial relief from buring sensation. The paste of sodium hydrogen carbonate completely neutralises the effect of the acid. |
|
| 292. |
A metal cabonate X on rectin g with an acid agives a gas which when passsed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at anode udring electrolysis of brine is passsed on dry y, it gives a compound Z, used for disinfecting drinking water . Identify X,Y,G and Z. |
|
Answer» X is calcium carbonate and the gas evovled is carbon dioxide when calcium carbonate reats with acid . `CaCO_(3)+Dil.2HCIrarrCaCI_(2)+H_(2)O+CO_(2)uparrow` Solution Y is lime water `Ca(OH)_(2)+CO_(2)rarrCaCO_(3)downarrow+H_(2)O` The gs evolved at anode during electroysis of brine is chlorine (G) `2NaCI+2H_(2)Orarr2NaOH+CI_(2)(g)+H_(2)(g)` When chlorine gs is passed through dry `Ca(OH)_(2)(Y)`, it produces bleahing dpowder (Z) used ofr disinfecting dringking water . `Ca(OH_(2))+CI_(2)rarrCaOCI_(2)+G_(2)O` Hence Z is calcium xoy chloride `(CaOCI_(2))` or bleacking powder. |
|
| 293. |
A teacher showed demonstration of action of acids on the metals in the laboratory. After the activity was over, one naughty student took an alluminium rod. He dipped it in a bottle containing concentrated nitric acid. Later, he dipped it in a beaker containing dilute `H_(2)SO_(4)` But, he did not find any bubbles coming out. He was surprised because he was able to see bubbles coming out when a metal rod is dipped in sulphuric acid when teacher did the experiment. He then approached the teacher and asked what is wrong with his activity. Predict the answer given by the teacher. |
| Answer» `HNO_(3)` is highly corrosive in nature. As a result it forms an oxide layer on A1 rod which acts as a passive layer. This passive layer prevents the reaction between A1 and `H_(2)SO_(4)`. And hence no liberation of hydrogen gas. | |
| 294. |
Which among the following statements is false ?A. Every protonic acid has its conjugate acidB. Pair of Bronsted acid and base that differ by a proton is conjugate acid-base pairC. A substance that accepts an electron pair to form co-ordinate covalent bond is an acidD. Arrhenius theory is confined to aqueous solution |
| Answer» Every protonic acid has a conjugate base | |
| 295. |
Which of the following is acidic in nature ?A. Lime juiceB. Human bloodC. Lime waterD. Antacid |
|
Answer» Correct Answer - A Lime juice is acidic in nature because it ontains cirtic . Human blood is slightly basic (i.e having pH 7.8) Lime water and antacid are basic in nature as they contain hydroxide `(OH^(-))` ion. |
|
| 296. |
If a few drops of a concetrated acid accidentally spiolls over the hand of student what should be done?A. wash the hand with saline solutionB. wash the hand immediately with plenty of water and appy a plaste of sodium hydrogen carbonateC. After washing woth plenty of water apply solution of sodium hbydroxide on the handD. Neutralise the acid with a strong alkali |
|
Answer» Correct Answer - B Wash the hand immediateely with plenty of water to wash away most of the acid annd then apply a paste of baking soda `(NaHCO_(3))` to neutralise the little acid left . Here a stong base cannot be used to neutralise the acid due to its corrosoive nature. |
|
| 297. |
Molecular formula for sodium oxide is ………… (a) Na2O (b) NaO2 (c) NaO (d) Na2O2 |
|
Answer» Correct option is: (a) Na2O |
|
| 298. |
Molecular formula of crystalline alum is ………(a) KSO4 , AlSO4 , 24H2O (b) K2SO4 , AISO4 , 24H2O(c) K2SO4 , Al2(SO4)3 , 24H2O (d) KSO4 , Al2(SO4)3 , 24H2O |
|
Answer» Correct option is: (c) K2SO4 , Al2(SO4)3 , 24H2O |
|
| 299. |
Which of the following substances will not give carbon dioxide on treatment with dilute acid ?A. MarbleB. Lime stoneC. Baking sodaD. Lime |
|
Answer» Correct Answer - D Since lime (CaO) does not contain carbon, it will not give any carbon dioxide gas. |
|
| 300. |
Methyl orange turns lime water _______ . |
|
Answer» Correct Answer - yellow Methyl orange turns lime water yellow. |
|