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 1911: Which of the following processes leads to increase in entropy? Options:
  A) Mixing a sample of NaCl and sand
  B) Condensation of water vapour
  C) Boiling a sample of water
  D) Cooling a saturated solution
  Show Answer
  The correct answer is C .
• Question 1912: Tartaric acid is used industrially to Options:
  A) make baking powder
  B) make fruit juice
  C) remove rust
  D) dry substance
  Show Answer
  The correct answer is A .
• Question 1913: A reaction takes places spontaneously if?
  Options:
  A) ∆G = O
  B) ∆S < O and ∆H > O
  C) ∆H < T ∆S
  D) ∆G > O
  Show Answer
  The correct answer is C .
• Question 1914: The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as Options:
  A) an allotropic oxide
  B) an amphoteric oxide
  C) a peroxide
  D) a dioxide
  Show Answer
  The correct answer is B .
• Question 1915: Which of the following, in clear solution, forms a white precipitate when carbon (IV) oxide is bubbled into it for a short time? Options:
  A) KOH
  B) NaOH
  C) Ca(OH)₂
  D) AI(OH)₃
  Show Answer
  The correct answer is C .
• Question 1916: Which of the following metals burn with brick red flame? Options:
  A) Pb
  B) Ca
  C) Na
  D) Mg
  Show Answer
  The correct answer is B .
• Question 1917:

  What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

  Options:
  A) 10cm${}^3$
  B) 12cm${}^3$
  C) 14cm${}^3$
  D) 16cm${}^3$
  Show Answer
  The correct answer is D .
• Question 1918:

  Which of the following pollutants will lead to the depletion of ozone layer?

  Options:
  A) chlorofluorocarbon
  B) carbon (ii) oxide
  C) hydrogen sulphide
  D) sulphur (iv) oxide
  Show Answer
  The correct answer is A .
• Question 1919: The alkanol obtained from the production of soap is Options:
  A) propanol
  B) ethanol
  C) glycerol
  D) methanol
  Show Answer
  The correct answer is C .
• Question 1920: The most suitable metal that can be used as lightning conductor is Options:
  A) silver
  B) copper
  C) iron
  D) aluminium
  Show Answer
  The correct answer is B .