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 1181:

  The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as;

  Options:
  A) saponification
  B) dehydration
  C) esterification
  D) hydrolysis
  Show Answer
  The correct answer is C .
• Question 1182: In the electrolysis of CuSO_4(g) using platinum electrodes, the reaction at the anode is Options:
  A) 4H⁺ + 4e^- → 2H₂
  B) 4OH^- - 4e^- → 2H₂O + O₂
  C) 2OH - 2e^- → 2OH
  D) 2OH^- + 2OH^- → 2H₂O + O₂
  Show Answer
  The correct answer is B .
• Question 1183: 10.0 dm³ of water was added to 2.0 mol dm^-3 of 2.5dm³ solution of HCl. What is the concentration of the final solution in mol dm^-3? Options:
  A) 0.4
  B) 8.0
  C) 2.0
  D) 0.5
  Show Answer
  The correct answer is A .
• Question 1184: ¹⁴₇N + X → ¹⁷₈O + ¹₁ H. In the above reaction, X is a? Options:
  A) neutron
  B) helium atom
  C) litgium atom
  D) deuterium atom
  Show Answer
  The correct answer is B .
• Question 1185: A piece of burning sulphur will continue to burn in a gas jar of oxygen to give misty fumes which readily dissolved in water. The resulting liquid is Options:
  A) sulphur (VI) trioxide
  B) tetraoxosulphate (VI) acid
  C) trioxosulphate (IV) acid
  D) dioxosulphate (II) acid
  E) hydrogen sulphide
  Show Answer
  The correct answer is C .
• Question 1186: If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ? Options:
  A) a drying agent
  B) an oxidizing agent
  C) a dehydrated agent
  D) a reducing agent
  E) a hydrolysing agent
  Show Answer
  The correct answer is C .
• Question 1187:

  

  Use the following option above to answer this question. Which of the following is the functional group of carboxylic acids?

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is D .
• Question 1188: A hydrogen atom which has lost an electron contains Options:
  A) one proton only
  B) one neutron only
  C) one proton and one neutron
  D) one proton, one electronic and one neutron
  Show Answer
  The correct answer is A .
• Question 1189: When 50cm³ of a saturated solution of sugar (molar mass 342.0g) at 40^oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40^oC is Options:
  A) 10.0 moles dm^-3
  B) 7.0 moles dm^-3
  C) 3.5 moles dm^-3
  D) 2.0 moles dm^-3
  Show Answer
  The correct answer is D .
• Question 1190: Chlorine gas turns damp starch-iodide paper Options:
  A) pink
  B) colourless
  C) red
  D) dark blue
  Show Answer
  The correct answer is D .