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 521: Which of the following can have an isomer? Options:
  A) C₂H₄
  B) C₄H₁₀
  C) C₃H₈
  D) C₂H₆
  E) C₆H₆
  Show Answer
  The correct answer is B .
• Question 522:

  The number of grammes of potassium hydroxide in 250cm³ of one molar solution is?

  (K = 39, O = 16, H = 1)

  Options:
  A) 40g
  B) 52g
  C) 100g
  D) 26g
  E) 14g
  Show Answer
  The correct answer is E .
• Question 523:

  How many alkoxyalkanes can be obtained from the molecular formula C${}_4$H${}_{10}$O?

  Options:
  A) 4
  B) 2
  C) 1
  D) 3
  Show Answer
  The correct answer is D .
• Question 524: Which ONE of the following statements is true? Options:
  A) All alkali metals salts dissolves with dissociation in water
  B) Most ionic substances are easily vaporized
  C) Ionic substances exist only as liquid
  D) Non-ionic substances are good electrolytes
  E) Nitrogen exists in a trivalent state in ammonium salts
  Show Answer
  The correct answer is A .
• Question 525: Hydrogen is used in oxy-hydrogen flames for melting metals because it Options:
  A) evolves a lot of heat when burnt
  B) combines explosively with oxygen
  C) is a very light gas
  D) is a rocket fuel
  Show Answer
  The correct answer is A .
• Question 526:

  HCL_(aq) + H₂O_(l) H₃O⁺_(aq) + Cl^-_(aq)

  In the reaction above, Cl^-_(aq) is the

  Options:
  A) conjugate acid
  B) acid
  C) conjugate base
  D) base
  Show Answer
  The correct answer is C .
• Question 527: What is the pH of 0.001 mol dm^-3 solution of sodium hydroxide Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 528: Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by Options:
  A) heating the affected parts in order to boil off the petroleum
  B) mechanically stirring to dissolve the petroleum in water
  C) pouring organic solvents to dissolve the petroleum
  D) spraying the water with stergents
  E) cooling to freeze out the petroleum
  Show Answer
  The correct answer is C .
• Question 529: When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are; Options:
  A) nitrogen and carbondioxide
  B) the rare gases
  C) nitrogen and oxygen
  D) nitrogen and the rare gases
  E) nitrogen, carbondioxide and the rare gases
  Show Answer
  The correct answer is D .
• Question 530:

  What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm³ solution?

  [K₂CrO₄ = 194.2g mol^-1]

  Options:
  A) 0.97g
  B) 9.70g
  C) 19.42g
  D) 97.10g
  Show Answer
  The correct answer is A .