Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 771: Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it Options:
  A) is strongly oxidizing
  B) is volatile
  C) renders the metal passive
  D) forms a layer of oxide on the metal
  Show Answer
  The correct answer is A .
• Question 772: The scale of a chemical balance is made of iron plate and coated with copper electrolytically because Options:
  A) iron is less susceptible to corrosion than copper
  B) copper is twice as less susceptitible to corrosion as iron
  C) copper is less susceptible to corrosion than iron
  D) copper and iron are equally susceptible to corrosion
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  The correct answer is C .
• Question 773: How many coulombs of electricity are passed through a solution in which 6.5 amperes are allowed to run for 1.0 hour? Options:
  A) 3.90 x 10² coulombs
  B) 5.50 x 10³ coulombs
  C) 6.54 x 10³ coulombs
  D) 2.34 x 10⁴ coulombs
  Show Answer
  The correct answer is D .
• Question 774: The salt that will form a precipitate soluble in excess ammonia solution is Options:
  A) Ca(NO₃)₂
  B) Cu(NO₃₎₂
  C) Mg(NO₃₎₂
  D) Al(NO₃₎₃
  Show Answer
  The correct answer is B .
• Question 775:

  (I). 3CuO(s) + 2NH3(g) -----> 3Cu(s) + 3H2O(l) + N2(g) 

  (II). 2NH3(g) + 3Cl2(g) -----> 6HCl(g) + N2(g) 

  (III). 4NH3(g) + 3O2(g) -----> 6H2O(l) + N2(g) 

  The reactions represented by the equations above demonstrate the

  Options:
  A) basic properties of ammonia
  B) acidic properties of ammonia
  C) reducing properties of ammonia
  D) oxidizing properties of ammonia
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  The correct answer is C .
• Question 776: Which of the following is acceptable as the organic product of the reaction of ethanoic acid and ethanol with an acid catalyst? Options:
  A) Ethyl ethanoate
  B) Methyl ethanoate
  C) Ethyl methyl ketone
  D) Butanol
  E) None
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  The correct answer is A .
• Question 777: In the extraction of iron, the waste gas from the furnace is a mixture of Options:
  A) PH₃ CO and CO₂
  B) CO and C
  C) N₂ CO and CO₂
  D) PH₃ and CO
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  The correct answer is A .
• Question 778: Suitable reagents for the laboratory preparation nitrogen are? Options:
  A) sodium dioxonitrate (III) and ammonium chloride
  B) sodium dioxonitrate (V) and ammonium chloride
  C) sodium chloride and ammonium chloride
  D) sodium chloride and ammonium diozonitrate (III)
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  The correct answer is A .
• Question 779: A suitable reagent for distinguish between ethanoic and ethanol is Options:
  A) bromine water
  B) Fehling’s solution
  C) sodium hydrogen trioxocarbonate (iv)
  D) Ammoniacal silver trioxonitrate(V)
  Show Answer
  The correct answer is C .
• Question 780: Diffusion is slowest in solid particles than in particles of liquid and gases because Options:
  A) solid particles have more kinetic energy than the particles of liquid and gases
  B) solid particles have less kinetic energy than the particles of liqiud and gases
  C) solid particles have less restriction in their movement than liquid and gas particles
  D) the particles in solids are far apart and the cohesive forces between them are negligible
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  The correct answer is B .