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 621: Starch can be converted to ethyl alcohol by? Options:
  A) distillation
  B) fermentation
  C) isomerization
  D) cracking
  Show Answer
  The correct answer is B .
• Question 622: In two separate experiments, 0.36g and 0.71g of chlorine combined with a metal X to give Y and Z respectively. An analysis showed that Y and Z contain 0.20g and 0.40g of X respectively. The data above represents the law of ? Options:
  A) multiple proportion
  B) conservation of mass
  C) constant composition
  D) reciprocal proportion
  Show Answer
  The correct answer is C .
• Question 623: An example of aromatic compound is? Options:
  A) C₆H₁₃OH
  B) C₆H₁₃CI
  C) C₆H₅OH
  D) C₆H₁₄
  Show Answer
  The correct answer is C .
• Question 624: The intermediate product formed when ethanol is progressively oxidized to ethanoic acid with potassium heptaoxodichromate (IV) is Options:
  A) butanal
  B) ethanal
  C) methanal
  D) propanal
  Show Answer
  The correct answer is B .
• Question 625:

  Alkanes are used mainly?

  Options:
  A) in the textile industry
  B) in the hydrogenation of oils
  C) as domestic and industrial fuels
  D) as fine chemicals
  Show Answer
  The correct answer is C .
• Question 626: A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone Options:
  A) distillation
  B) sublimation
  C) precipitation
  D) evaporation
  E) decomposition
  Show Answer
  The correct answer is B .
• Question 627: The following arrangement of elements in order of decreasing number of outer electrons; One of the elements is wrongly placed. Which is it? ALUMINIUM, CHLORINE, SILICON, MAGNESIUM AND SODIUM. Options:
  A) chlorine
  B) aluminium
  C) silicon
  D) magnesium
  E) sodium
  Show Answer
  The correct answer is B .
• Question 628: The minimum volume of oxygen required for the complete combustion of a mixture of 10cm ³ of CO and 15 cm ³ of H ² is Options:
  A) 25.0cm³
  B) 12.5 cm³
  C) 10.0 cm³
  D) 5.0cm³
  Show Answer
  The correct answer is C .
• Question 629: Which of the following samples will react fastest with dilute trioxonitrate (V) acid? Options:
  A) 5 g of lumps of CacO₃ at 25°C
  B) 5 g of powered CacO₃ at 25°
  C) 5 g of lumps of CaCO₃ at 50°C
  D) 5 g of powered CaCO₃ AT 50°C
  Show Answer
  The correct answer is D .
• Question 630: Which of the following does NOT contain aluminium as component? Options:
  A) Over-head cables
  B) Duralumin
  C) Container for caustic soda
  D) Container for nitric acid
  Show Answer
  The correct answer is D .