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 1891:

  When an acidic solution is diluted, what happens to its pH?

  Options:
  A) It depends on the specific acid
  B) It decreases
  C) It remains the same
  D) It increases
  Show Answer
  The correct answer is D .
• Question 1892: In a neutralization reaction involving HCI and NaOH using litmus as indicator, the colour at the end point is Options:
  A) Blue
  B) Red
  C) Orange
  D) Purple
  Show Answer
  The correct answer is C .
• Question 1893: Which of the following pair of gases will NOT react further with oxygen at a temperature between 30^oC AND 400^oC Options:
  A) SO₂ and NH₃
  B) CO₂ and H₂
  C) NO₂ and SO₃
  D) SO₃ and NO
  E) CO and H₂
  Show Answer
  The correct answer is C .
• Question 1894:

  C_(s) + 2S_(g) → CS_2(g)

  ΔH = +89 kJ mol^-1

  The chemical equation above implies that

  Options:
  A) each of carbon and sulphur has 89 kJ of energy
  B) both carbon and sulphur contribute 89 kJ of energy
  C) 89 kJ of energy is released
  D) 89 kJ of energy is absorbed
  Show Answer
  The correct answer is D .
• Question 1895: The flame used by welders in cutting metals is Options:
  A) butane gas flame
  B) acetylene flame
  C) kerosene flame
  D) oxy-acetylene flame
  E) oxygen flame
  Show Answer
  The correct answer is D .
• Question 1896: The compounds CH₃CH₂CHO and CH₃COCH₃ can be distinguished from each other using Options:
  A) Dilute ammonia
  B) Benedict's solution
  C) Tollen's reagent
  D) Sodium hydroxide solution
  Show Answer
  The correct answer is C .
• Question 1897:

  The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO${}_3$ is treated with 0.2dm${}^3$ of 1 Mole of HCL in the equation

  CaCO${}_3$ + 2HCL $\to$ CaCl${}_2$  + H${}_2$ O + CO${}_2$  , is ?

  Options:
  A) 1.00 X 10${}^{23}$
  B) 6.02 X 10${}^{23}$
  C) 6.02 X 10${}^{22}$
  D) 6.02 X 10${}^{24}$
  Show Answer
  The correct answer is C .
• Question 1898:

  An element having the atomic number 17 will resemble which of the following elements having atomic number as given below?

  Options:
  A) 33
  B) 35
  C) 18
  D) 19
  Show Answer
  The correct answer is B .
• Question 1899:

  

  The lUPAC name for

  Options:
  A) 1-methyl pentane
  B) 3-methylbutane
  C) 2-methylbutane
  D) 1-dimethyl propane
  Show Answer
  The correct answer is C .
• Question 1900: Which of the following is an electrolyte? Options:
  A) alcohol
  B) sodium ethanoate
  C) solid potassium hydroxide
  D) mercury
  Show Answer
  The correct answer is B .