This quiz works best with JavaScript enabled. Home > Cbse > Class 7 > Science > Bases > Class 7 Science Chapter 4 Bases – Quiz 6 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 7 Science Chapter 4 Bases Quiz 6 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Which scientist contributed the majority of the work and research necessary for understanding the structure of DNA? A) Francis Crick. B) James Watson. C) Rosalind Franklin. D) None of the above. Show Answer Correct Answer: C) Rosalind Franklin. 2. Turns blue litmus red A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 3. Which of the following statements is correct about the weak base, ammonia (NH$_{3}$)? A) It dissociates completely in water to produce a high concentration of hydroxide ions. B) It dissociates partially in water to produce a low concentration of hydrogen ions. C) It dissociates partially in water to produce a high concentration of hydroxide ions. D) It dissociates partially in water to produce a low concentration of hydroxide ions. Show Answer Correct Answer: D) It dissociates partially in water to produce a low concentration of hydroxide ions. 4. A strong base in a water solution A) Completely dissociates into ions. B) Is a weak electrolyte. C) Will not dissolve. D) Produces many H$^{+}$ ions. Show Answer Correct Answer: A) Completely dissociates into ions. 5. What is Microsoft Access? A) A spreadsheet. B) A database. C) Database Manager. D) Un Parche de Office. Show Answer Correct Answer: C) Database Manager. 6. Solve the equation:$2=2^{3x-2}$ A) X =-5. B) X = 1. C) X =-3. D) X = 2. Show Answer Correct Answer: B) X = 1. 7. What is responsible for holding the two strands of the DNA double helix together? A) Hydrogen bonds. B) Alleles. C) London dispersion forces. D) Deoxyribose sugars. Show Answer Correct Answer: A) Hydrogen bonds. 8. What is there more of in solution with a weak acid? A) Reactants. B) Products. C) Both are equal. D) Neither. Show Answer Correct Answer: A) Reactants. 9. Strong acids will have a A) Low concentration of hydroxide ions. B) Low concentration of hydronium ions. C) High concentration of hydroxide ions. D) High concentration of hydronium ions. Show Answer Correct Answer: D) High concentration of hydronium ions. 10. A neutral solution A) It has the same amount of H+ ions and Oh-ions. B) It has more H+ ions than Oh-. C) It has less amount of H+ ions than oh-. D) None of the above. Show Answer Correct Answer: A) It has the same amount of H+ ions and Oh-ions. 11. Weak acid will have a A) Low concentration of hydronium ions. B) High concentration of hydronium ions. C) High concentration of hydroxide ions. D) Low concentration of hydroxide ions. Show Answer Correct Answer: A) Low concentration of hydronium ions. 12. A substance with a pH of 7 is A) A base. B) An acid. C) Neutral. D) None of the above. Show Answer Correct Answer: C) Neutral. 13. What does the Latin root aqua mean? A) Dirt. B) Water. C) Sand. D) Ocean. Show Answer Correct Answer: B) Water. 14. A substance is found to turn phenolpthalein magenta (pink). Predict what will happen when blue and red litmus paper is placed into the substance. A) The blue litmus will stay blue and the red litmus will stay red. B) The blue litmus will stay blue and the red litmus will turn blue. C) The blue litmus will turn red and the red litmus will stay red. D) The blue litmus will turn red and the red litmus will turn blue. Show Answer Correct Answer: B) The blue litmus will stay blue and the red litmus will turn blue. 15. During an experiment about the rate of dissolving you test temperature. In one beaker you use room temperature water, one beaker you use hot water and the last beaker you use ice water. In what order would the beakers dissolve the solute from slowest to fastest? A) Hot, room temperature, cold. B) Cold, room temperature, hot. C) Cold, hot, room temperature. D) Hot, cold, room temperature. Show Answer Correct Answer: B) Cold, room temperature, hot. 16. HSO$_{4}$$^{-}$(aq)+H$_{2}$O(l) $\rightarrow$ H$_{3}$O$^{+}$(aq)+SO$_{4}$$^{2-}$(aq)Identify the Acid in the above reaction. A) H$_{2}$O. B) HSO $ _ {4} $$^{-} $. C) SO$_{4}$$^{2-}$. D) H$_{3}$O$^{+}$. Show Answer Correct Answer: B) HSO $ _ {4} $$^{-} $. 17. Are characteristics of acids except A) They contain non-metals. B) They have a sour taste. C) PH DE 1-7. D) Formed by OH. Show Answer Correct Answer: D) Formed by OH. 18. Which one feels slippery A) A base. B) An acid. C) A neutral. D) None of the above. Show Answer Correct Answer: A) A base. 19. All substances are either acidic or basic A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 20. Solve the equation:$8^{3x-4}=8^{2x+1}$ A) X =-2. B) X = 5. C) X = 4. D) X = 3. Show Answer Correct Answer: B) X = 5. 21. Vinegar CH$_{3}$COOH is ..... A) An acid. B) A base. C) A salt. D) None of the above. Show Answer Correct Answer: A) An acid. 22. Which 2 molecules form the sides (backbone) of the DNA ladder? A) Deoxyribose sugar and adenine. B) Deoxyribose sugar and a hydrogen bond. C) Deoxyribose sugar and the nucleus. D) Deoxyribose sugar and phosphate. Show Answer Correct Answer: D) Deoxyribose sugar and phosphate. 23. On the pH scale the range of greater than 7 to 14 corresponds to substances: A) Saladas. B) Acidic. C) Basic. D) None. Show Answer Correct Answer: C) Basic. 24. In the structure of DNA which one of the following binds with cytosine? A) Thymine. B) Adenine. C) Dexoxyribose. D) Within limits. Show Answer Correct Answer: C) Dexoxyribose. 25. What does the Latin root ject mean? A) To write. B) Bad. C) Mother. D) To throw. Show Answer Correct Answer: D) To throw. 26. How can I enter data to a table? A) Through a form. B) By means of a report. C) Through a consultation. D) Through a macro. Show Answer Correct Answer: A) Through a form. 27. Barium hydroxide(barium is a +2 ion, hydroxide is a-1 ion) A) Baoh. B) Ba $ _ {2} $ oh. C) Ba (oh) $ _ {2} $. D) None of the above. Show Answer Correct Answer: C) Ba (oh) $ _ {2} $. 28. An extreme acid will have a ph of A) 13. B) 7. C) 1. D) 6. Show Answer Correct Answer: C) 1. 29. Which of the following is a property of acids? A) They have a bitter taste. B) They turn litmus paper blue. C) They react with metals to produce hydrogen gas. D) They have a slippery feel. Show Answer Correct Answer: C) They react with metals to produce hydrogen gas. 30. Change 351 $ _ {10} $ to a number in base eight.Change 351 $ _ {10} $ to number in basis eight. A) 547$_{8}$. B) 532$_{8}$. C) 637$_{8}$. D) 537$_{8}$. Show Answer Correct Answer: D) 537$_{8}$. 31. Is the following substance an acid or a base? Ca(OH)2 A) Acid. B) Base. C) All the above. D) None of the above. Show Answer Correct Answer: B) Base. 32. 8 $^{} $$^{zx+h} $ = 8 $^{w} $ A) X=12. B) X=28. C) X=1. D) X=3. Show Answer Correct Answer: C) X=1. 33. Vinegar is an example of A) Acid. B) Base. C) Neither acid or base. D) None of the above. Show Answer Correct Answer: A) Acid. 34. Say the name of this compound NaOH A) Formic acid. B) Hydrogenic acid. C) Sodium hydroxide. D) Hydrochloric acid. Show Answer Correct Answer: C) Sodium hydroxide. 35. In RNA, which nitrogen base pairs with adenine? A) Thymine. B) Guanine. C) Cytosine. D) Uracil. Show Answer Correct Answer: D) Uracil. 36. Turns bright pink in a strong base ..... A) Citric Acid. B) Phenolphthalein. C) Distilled water. D) Blue litmus paper. Show Answer Correct Answer: B) Phenolphthalein. 37. Which experiment demonstrated that DNA is the genetic material? A) Avery-MacLeod-McCarty experiment. B) Griffith's transformation experiment. C) Mendel's pea plant experiment. D) Hershey-Chase experiment. Show Answer Correct Answer: D) Hershey-Chase experiment. 38. Sometimes DNA is referred to as a "polymer of nucleotides" . What does this mean? A) DNA is a long chain of nucleotide monomers. B) DNA is found in the nucleus of many cells. C) DNA is the 'glue' which sticks nucleotides together. D) DNA is a nucleotide made from many parts. Show Answer Correct Answer: A) DNA is a long chain of nucleotide monomers. 39. If you have a pH of 4, what is the pOH A) 12. B) 8. C) 10. D) 57. Show Answer Correct Answer: C) 10. 40. The roots mit or miss (from Latin) mean "send." A missive is a form of written communication, usually a letter.You need permission to park your car in a certain place.If you "transmit" a message, you A) Keep it a secret. B) Destroy it. C) Write it down for yourself to remember. D) Send it from one person to another. Show Answer Correct Answer: D) Send it from one person to another. 41. "A lit splint gives a squeaky pop" is a test for which gas? A) Carbon dioxide. B) Air. C) Hydrogen. D) Oxygen. Show Answer Correct Answer: C) Hydrogen. 42. How does the concentration of an alkali differ from its strength? A) Concentration is related to the solubility of an alkali. B) Strength is determined by how much hydroxyl ion is produced. C) Strength refers to the amount of alkali dissolved. D) Concentration affects the dissociation of alkalis. Show Answer Correct Answer: B) Strength is determined by how much hydroxyl ion is produced. 43. Which base is found in soap A) Potassium oxide. B) Sodium oxide. C) Sodium cloride. D) Sodium hydroxide. Show Answer Correct Answer: D) Sodium hydroxide. 44. Select the formula for the following base:sodium hydroxide A) NaOH. B) To $ _ {} $ (oh) $ _ {2} $. C) NaH. D) None of the above. Show Answer Correct Answer: A) NaOH. 45. The rules of DNA pairing states that Cytosine (C) always pairs up with A) Guanine. B) Cytosine. C) Adenine. D) Thymine. Show Answer Correct Answer: A) Guanine. 46. How can the strength of an alkali be determined? A) By the amount of hydroxyl ions it produces in water. B) By its concentration in water. C) By its solubility in water. D) By its color in litmus test. Show Answer Correct Answer: A) By the amount of hydroxyl ions it produces in water. 47. The difference between the values of the digits 2 in the number $3212_5$ A) 8. B) 52. C) 12. D) 48. Show Answer Correct Answer: D) 48. 48. A turmeric paper was fist dipped in a washing soda solution, then the same turmeric paper was dipped in HCl. What will be the final colour of the turmeric paper? A) No colour change. B) Yellow colour. C) Data given not sufficient. D) Brownish red. Show Answer Correct Answer: B) Yellow colour. 49. What does DNA do? A) It carries genetic codes from parents to offspring. B) It carries oxygen from the lungs to the body. C) It tells you who you are. D) It defines the organism. Show Answer Correct Answer: A) It carries genetic codes from parents to offspring. 50. Which solution reacts with LiOH to produce a salt and water? A) CaO. B) KCl. C) NaOH. D) H2SO4. Show Answer Correct Answer: D) H2SO4. 51. Which organelle is DNA usually found in? A) Cell membrane. B) Ribosome. C) Vacuole. D) Nucleus. Show Answer Correct Answer: D) Nucleus. 52. Select the formula for the following acid:nitrous acid A) HNO$_{2}$. B) HNO$_{3}$. C) H$_{3}$N. D) None of the above. Show Answer Correct Answer: A) HNO$_{2}$. 53. If there is excess hydrogen ions, the solution will be ..... A) Acidic. B) Basic. C) All the above. D) None of the above. Show Answer Correct Answer: A) Acidic. 54. Name the following compound Fe(OH)$_{2}$ A) Iron hydroxide. B) Iron oxygen hydroxide. C) Iron monoxide hydroxide. D) Iron (III) hydroxide. Show Answer Correct Answer: A) Iron hydroxide. 55. The ion released by all the bases when they are placed in water is: A) OH$^{-}$. B) OH$^{+}$. C) O$^{-}$. D) H$^{+}$. Show Answer Correct Answer: A) OH$^{-}$. 56. What effect does a base have on litmus paper? A) It turns blue litmus paper red. B) It has no effect on litmus paper. C) It bleaches litmus paper. D) It turns red litmus paper blue. Show Answer Correct Answer: D) It turns red litmus paper blue. 57. Reacts with metals to give off a gas A) Acid. B) Base. C) Neutral. D) None of the above. Show Answer Correct Answer: A) Acid. 58. Soap is an example of ..... A) A base. B) An acid. C) A neutral substance. D) None of the above. Show Answer Correct Answer: A) A base. 59. Which of the following is true about alkalis? A) Alkalis are insoluble in water. B) Alkalis do not produce hydroxyl ions in water. C) Alkalis are bases that are soluble in water. D) All alkalis are acids. Show Answer Correct Answer: C) Alkalis are bases that are soluble in water. 60. Which of the following is not a cause of acid rain? A) Combustion engines. B) Burning of fossil fuels. C) Volcanic eruptions. D) Electric cars. Show Answer Correct Answer: D) Electric cars. ← PreviousNext →Related QuizzesScience QuizzesClass 7 QuizzesClass 7 Science Chapter 4 Bases Quiz 1Class 7 Science Chapter 4 Bases Quiz 2Class 7 Science Chapter 4 Bases Quiz 3Class 7 Science Chapter 4 Bases Quiz 4Class 7 Science Chapter 4 Bases Quiz 5Class 7 Science Chapter 4 Bases Quiz 7Class 7 Science Chapter 4 Bases Quiz 8Class 7 Science Chapter 4 Bases Quiz 9 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books