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 371:

  

  Use the diagram above to answer this question.

  The reaction taking place in the flask above is known as

  Options:
  A) hydrolysis
  B) double decomposition
  C) dehydration
  D) pyrolysis
  Show Answer
  The correct answer is C .
• Question 372: The enzyme used in the hydrolysis of starch to dextrin and maltose is Options:
  A) Zymase
  B) Sucrase
  C) Amylase
  D) Lactase
  Show Answer
  The correct answer is C .
• Question 373: the elements that belong to the third period of the periodic table are Options:
  A) Li, Be, Al and P
  B) Na, P, O and Cl
  C) B, C, N and O
  D) Nz, Mg, S and Ar
  Show Answer
  The correct answer is D .
• Question 374:

  CH₃-CH-CH₃

  CH₂CI Is known as?

  Options:
  A) 1-chloro-2-methylbutane
  B) 1-chloro-2-methylpropane
  C) 2-chloromethylpropane
  D) 1-chloro-2, 2-dimethylethane
  Show Answer
  The correct answer is B .
• Question 375: The function of conc. H₂SO₄ in the esterification of ethanoic acid with ethanol is to Options:
  A) serve as a dehydrating agent
  B) serve as a solvent
  C) act as a catalyst
  D) prevent any side reaction
  E) serve as an oxidizing agent
  Show Answer
  The correct answer is C .
• Question 376: In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm³ of 1.25 molar sulphuric acid? Options:
  A) 5cm³
  B) 10cm³
  C) 20cm³
  D) 25cm³
  E) 50cm³
  Show Answer
  The correct answer is E .
• Question 377:

  Which of the following is a common property of non-metals?

  Options:
  A) Exist as solids at room temperature
  B) Tend to gain electrons in chemical reactions
  C) High thermal conductivity
  D) Readily form cations in chemical reactions
  Show Answer
  The correct answer is B .
• Question 378:

  In the electrolysis of dilute sulphuric acid using platinum electrodes, the products obtained at the anode and cathode are:

  Anode Cathode

  Options:
  A) Sulphur hydrogen
  B) Hydrogen oxygen
  C) Oxygen Hydrogen
  D) Hydrogen sulphate ions
  E) Sulphur oxygen
  Show Answer
  The correct answer is C .
• Question 379:

  The solubility of the solids that dissolves in a given solvent with the liberation of heat will

  Options:
  A) increase with an increase in temperature
  B) decrease with an increase in temperature
  C) decrease with a decrease in temperature
  D) not be affected by changes in temperature
  Show Answer
  The correct answer is A .
• Question 380: The shape of ammonia molecules is Options:
  A) trigonal planar
  B) octahedral
  C) square planar
  D) tetrahedral
  Show Answer
  The correct answer is A .