Tiêu đề 2 Acids, Bases and Salts - MCQs.pdf ✅

© www.bankofbiology.com 8921 510 476 1 2. ACIDS, BASES AND SALTS - MCQs 1. What causes sour and bitter tastes in food? a. Sugars and salts respectively b. Acids and bases respectively c. Proteins and fats respectively d. Vitamins and minerals respectively Answer: b) Acids and bases respectively 2. Which of the following is NOT a natural indicator? a. Litmus b. Red cabbage leaves c. Turmeric d. Methyl orange Answer: d) Methyl orange 3. From which organism is litmus solution extracted? a. Bacteria b. Algae c. Lichen d. Fungi Answer: c) Lichen 4. Colour of neutral litmus solution is a. Blue b. Red c. Purple d. Green Answer: c) Purple 5. What change does blue litmus undergo in the presence of an acid? a. Turns red b. Turns green c. Turns purple d. No change Answer: a) Turns red 6. What change does red litmus undergo in the presence of a base? a. Turns yellow b. Turns blue c. Turns purple d. No change Answer: b) Turns blue 7. What happens to a curry stain on a white cloth when rubbed with soap and then washed with water? a. Turns blue and stays blue b. Turns reddish-brown and stays reddish-brown c. Turns reddish-brown and then turns yellow again d. Turns yellow and then turns reddish-brown Answer: c) Turns reddish-brown and then turns yellow again 8. Which of the following is a synthetic indicator? a. Litmus b. Turmeric c. Phenolphthalein d. Red cabbage leaves Answer: c) Phenolphthalein 9. The indicator present in curry that reacts with soap is a. Litmus b. Red cabbage c. Turmeric d. Phenolphthalein Answer: c) Turmeric UNDERSTANDING THE CHEMICAL PROPERTIES OF ACIDS & BASES 10. Acids in red litmus solution will produce a. Blue colour b. Pinkish red c. Yellow colour d. No change in colour Answer: d) No change in colour 11. Acids in blue litmus solution will produce a. Red colour b. Pinkish red c. Yellow colour d. No change in colour Answer: a) Red colour 12. The change that occurs on addition of an acid to Phenolphthalein solution and Methyl orange solution respectively is a. Pinkish red, colourless b. Colourless, Pinkish red c. Yellow, colourless d. Colourless, yellow Answer: b) Colourless, Pinkish red 13. Bases in red litmus solution will produce a. Blue colour b. Pinkish red c. Yellow colour d. No change in colour Answer: a) Blue colour 14. Bases in blue litmus solution will produce a. Blue colour b. Pinkish red c. Yellow colour d. No change in colour Answer: d) No change in colour 15. Which of the following is an olfactory indicator? a) Litmus b) Clove oil c) Methyl orange d) Phenolphthalein Answer: b) Clove oil 16. The change that occurs on addition of a base to Phenolphthalein solution and Methyl orange solution respectively is a. Pinkish red, colourless b. Colourless, Pinkish red c. Remains yellow, Red to pink d. Red to pink, Remains yellow Answer: d) Red to pink, Remains yellow 17. What happens to the odour of onion when it is treated with NaOH? a. The odour intensifies b. The odour vanishes c. The odour remains unchanged d. The odour changes to a sweet smell Answer: b) The odour vanishes
© www.bankofbiology.com 8921 510 476 2 18. What is the result of the test with vanilla essence when it is added to NaOH? a. The odour of vanilla intensifies b. The odour of vanilla vanishes c. The odour remains unchanged d. The odour changes to a different smell Answer: b) The odour of vanilla vanishes 19. When zinc granules react with dilute sulphuric acid, which gas is produced? a) Oxygen b) Nitrogen c) Carbon dioxide d) Hydrogen Answer: d) Hydrogen 20. What is the main product formed when an acid reacts with a metal? a) Base b) Salt c) Water d) CO2 Answer: b) Salt 21. What happens when a metal carbonate reacts with an acid? a. Salt and water are produced b. Salt and hydrogen are produced c. Salt, CO2 and water are produced d. Salt and oxygen are produced Answer: c) Salt, CO2 and water are produced 22. Which gas turns lime water milky? a) Hydrogen b) Oxygen c) Nitrogen d) Carbon dioxide Answer: d) Carbon dioxide 23. What is the reaction called when an acid reacts with a base? a) Precipitation b) Neutralisation c) Decomposition d) Oxidation Answer: b) Neutralisation 24. What are the products when calcium hydroxide reacts with carbon dioxide? a. Calcium carbonate and water b. Calcium chloride and water c. Calcium bicarbonate and water d. Calcium oxide and water Answer: a) Calcium carbonate and water 25. What is the general reaction between a metal oxide and an acid? a. Metal oxide + Acid → Base + Water b. Metal oxide + Acid → Salt + Water c. Metal oxide + Acid → Salt + Hydrogen d. Metal oxide + Acid → Base + Hydrogen Answer: b) Metal oxide + Acid → Salt + Water WHAT DO ALL ACIDS AND ALL BASES HAVE IN COMMON? 26. Which of the following generates hydrogen gas on reacting with metals? a) Glucose b) Alcohol c) Acids d) Bases Answer: c) Acids 27. What is the result of testing HCl gas with dry litmus paper? a. The litmus paper turns red b. The litmus paper turns blue c. The litmus paper does not change colour d. The litmus paper turns green Answer: c) The litmus paper does not change colour 28. What ions are produced by acids in aqueous solutions? a) OHions b) Na+ ions c) Clions d) H+ ions Answer: d) H+ ions 29. Which of the following is not an alkali? a) NaOH b) KOH c) NH4OH d) HCl Answer: d) HCl 30. The general reaction between an acid and a base is a. Acid + Base → Salt + Hydrogen b. Acid + Base → Salt + Water c. Acid + Base → Water + Carbon dioxide d. Acid + Base → Salt + Oxygen Answer: b) Acid + Base → Salt + Water 31. What is formed when NaOH dissolves in water? a) Na+ and H+ ions b) Na+ and OHions c) NaOH molecules d) Na2+ and OHions Answer: b) Na+ and OHions 32. Why is it dangerous to add concentrated acid to water without proper care? a. It produces a strong odor b. It is an endothermic reaction c. It can cause splashing and burns d. It makes the solution acidic Answer: c) It can cause splashing and burns 33. What happens to the concentration of ions when an acid or base is diluted with water? a. The concentration increases b. The concentration decreases c. The concentration remains the same d. The ions disappear Answer: b) The concentration decreases 34. Which of the following best describes the nature of alkalis?
© www.bankofbiology.com 8921 510 476 3 a. Sour and non-corrosive b. Soapy, bitter, and corrosive c. Sweet and non-reactive d. Odourless and inert Answer: b) Soapy, bitter, and corrosive HOW STRONG ARE ACID OR BASE SOLUTIONS? 35. What is the pH of a neutral solution? a) 0 b) 7 c) 14 d) 5.6 Answer: b) 7 36. Which of the following solutions is highly acidic? a) 1M NaOH b) Tap water c) Lemon juice d) Saliva (before meal) Answer: c) Lemon juice 37. What is the colour of pH paper in a solution of 1M NaOH? a) Red b) Green c) Yellow d) Dark blue Answer: d) Dark blue 38. What is the pH range for the ideal soil for plant growth? a) 4 to 5 b) 5 to 6 c) 6 to 7 d) 7 to 8 Answer: c) 6 to 7 39. Egg shell is made up of (a) CaCO3 (b) CaO (c) Ca(OH)2 (d) CaCl2 Answer: (a) CaCO3 40. What type of acid is produced by bacteria in the mouth, causing tooth decay? a) Citric acid b) Tartaric acid c) Methanoic acid d) Various acids below pH 5.5 Answer: d) Various acids below pH 5.5 41. What is the pH value of coffee, according to the provided text? a) 4.5 b) 6.0 c) 2.2 d) 7.0 Answer: a) 4.5 42. Which of the following is an example of a strong base? a) NH4OH b) NaOH c) CH3COOH d) H2SO4 Answer: b) NaOH 43. What happens to the pH of rainwater when it becomes acid rain? a. pH becomes more than 7 b. pH becomes less than 5.6 c. pH remains neutral d. pH becomes exactly 7 Answer: b) pH becomes less than 5.6 44. Which natural acid is found in tamarind? a) Citric acid b) Acetic acid c) Oxalic acid d) Tartaric acid Answer: d) Tartaric acid 45. Tooth enamel is made up of (a) calcium carbonate (b) calcium phosphate (c) calcium oxide (d) calcium chloride Answer: (b) calcium phosphate 46. Calcium phosphate present in tooth enamel is ............. (a) basic (b) acidic (c) neutral (d) amphoteric Answer: (a) basic 47. Which of the following types of medicines is used for treating indigestion? (a) Antibiotics (b) Analgesic (c) Antacid (d) Antiseptic Answer: (c) Antacid 48. What happens to the pH when a base is added to water? a) pH decreases b) pH increases c) pH remains the same d) pH becomes neutral Answer: b) pH increases 49. Assertion: Universal indicator gives green colour with distilled water. Reason: pH of distilled water is 7 and it is neutral and universal indicator gives green colour with neutral solution. a. Both A and R are true and R is the correct explanation of A. b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true. e. Both A and R are false. Answer: (a) MORE ABOUT SALTS 50. Which of the following pairs of salts belong to the same family of sodium salts? a) NaCl and Na2SO4 b) NaCl and KCl c) K2SO4 and Na2SO4 d) CaSO4 and Na2SO4 Answer: a) NaCl and Na2SO4
© www.bankofbiology.com 8921 510 476 5 51. What acid and base react to form potassium sulphate (K2SO4)? a) H2SO4 and NaOH b) H2SO4 and KOH c) HCl and KOH d) HNO3 and KOH Answer: b) H2SO4 and KOH 52. What is the chemical formula for sodium carbonate? a) NaHCO3 b) Na2CO3 c) NaCl d) Na2SO4 Answer: b) Na2CO3 53. What type of solution will have a pH value greater than 7? a) Neutral solution b) Acidic solution c) Basic solution d) None of the above Answer: c) Basic solution 54. Which of the following salts is formed from the reaction of HCl and NaOH? a) Na2SO4 b) NaCl c) NaNO3 d) NaHCO3 Answer: b) NaCl 55. What is the pH of sodium acetate solution? a) Less than 7 b) 14 c) Greater than 7 d) 7 Answer: c) Greater than 7 56. What process is used to produce sodium hydroxide from brine? a) Dehydration b) Electrolysis c) Neutralization d) Recrystallization Answer: b) Electrolysis 57. What gas is produced at the cathode during the electrolysis of brine? a) Chlorine b) Hydrogen c) Oxygen d) Carbon dioxide Answer: b) Hydrogen 58. What is the chemical name of baking soda? a) Sodium carbonate b) Sodium hydrogencarbonate c) Sodium chloride d) Sodium sulfate Answer: b) Sodium hydrogencarbonate 59. What is the chemical formula of Plaster of Paris? a) CaSO4.2H2O b) CaSO4.1⁄2 H2O c) CaCO3 d) CaCl2 Answer: b) CaSO4.1⁄2 H2O 60. What is formed when Plaster of Paris is mixed with water? a) Calcium carbonate b) Gypsum c) Baking soda d) Washing soda Answer: b) Gypsum 61. What is the pH of a solution of sodium chloride? a) Less than 7 b) 7 c) Greater than 7 d) 14 Answer: b) 7 62. Which compound is used in soda-acid fire extinguishers? a. Sodium chloride b. Sodium carbonate c. Sodium hydrogencarbonate d. Sodium sulfate Answer: c) Sodium hydrogencarbonate 63. What is the use of chlorine gas produced during the electrolysis of brine? a) Fuel b) Disinfectants c) Cooking d) Fertilizer Answer: b) Disinfectants 64. Which salt is formed from the reaction of HNO3 and NaOH? a) NaCl b) Na2SO4 c) NaNO3 d) Na2CO3 Answer: c) NaNO3 65. Which of the following is a weak acid? a) HCl b) H2SO4 c) CH3COOH d) NaOH Answer: c) CH3COOH 66. What is the common use of bleaching powder? a) De-greasing metals b) Water treatment c) Fuel d) Fertilizer Answer: b) Water treatment 67. What is produced when NaHCO3 is heated for cooking? a) NaCl b) Na2CO3 c) CO2 d) NaOH Answer: c) CO2 68. Which of the following salts is basic in nature? a) Na2CO3 b) NaCl c) CuSO4 d) KCl Answer: a) Na2CO3