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 1211: In an electrolytic set-up to protect iron from corrosion, the iron is? Options:
  A) made cathode
  B) made anode
  C) used with a metal of lower electropositive potential
  D) initially coated with tin
  Show Answer
  The correct answer is D .
• Question 1212: Coal gas is made up of carbon (II) oxide, hydrogen and? Options:
  A) nitrogen
  B) air
  C) argon
  D) methane
  Show Answer
  The correct answer is D .
• Question 1213:

  Na₂S₂O_3(aq) + 2HCl_(aq) → 2NaCl_(aq) + H₂O_(l)

  Which of the following would introduce the greatest increase in the rate of the chemical reaction above?

  Options:
  A) An increase in temperature and decrease in the concentration of the reactant
  B) A decrease in the volume and increase in the pressure of the reactant
  C) A decrease in the temperature and an incease in the concentration of the reactant
  D) An increase in temperature and an increase in the concentration of the reactant
  Show Answer
  The correct answer is D .
• Question 1214: Which of the following is NOT correct test for the named organic compound in each case? Options:
  A) Butanoic acid solution gives effervescence with Na₂CO₃ solution
  B) Glucose when reacted with Na₂CrO₄ at 0°C will show immediate discharge of colour
  C) When but-2-ene is reacted with dilute solution of KMnO₄ the purple colour of KMnO is discharged readily even room temperature
  D) When butan-2-ol is boiled with butanoic acid with a drop of concentrated H₂SO₄ a sweet smelling liquid is produced
  Show Answer
  The correct answer is B .
• Question 1215:

  Which of the following properties increases from left to right along the period but decreases down the group in the Periodic Table?

  I. Atomic Number   ii. Ionization energy  iii. Metallic character  iv. Electron affinity

  Options:
  A) ii and iii only
  B) ii and iv only
  C) iii and iv only
  D) i and ii only
  Show Answer
  The correct answer is B .
• Question 1216: $PC{l}_{5(g)}\to PC{l}_{3(g)}+C{l}_{2(g)}$
  In the reaction above, an increase in pressure will Options:
  A) decelerate the reaction
  B) Increase the yield of $PC{l}_3$
  C) increase the yield of $PC{l}_5$
  D) accelerate the reaction
  Show Answer
  The correct answer is C .
• Question 1217:

  For the reaction NH₄NO₂ $\to$ N₂ + 2H₂O, calculate the volume of nitrogen that would be produced at S. T. P from 320 g of the dioxonitrate(iii)salt. (Relative atomic masses: N = 14, O = 16, H = 1)

  Options:
  A) 2.24 dm ³
  B) 224 dm³
  C) 1.12 dm ³
  D) 112 dm ³
  E) 4.48 dm ³
  Show Answer
  The correct answer is D .
• Question 1218: A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T? Options:
  A) is deliquescent
  B) is hydroscopic
  C) has some molecules of water of crystallization
  D) is efflorescent
  Show Answer
  The correct answer is A .
• Question 1219: 9.8g of solid potassium chlorate (KCIO₃) were added to 40 cm³ of water and heated to dissolve all the solid. As he solution cooled, crystals of potassium chlorate started forming at 60°C. The solubility of potassium chlorate at 66°C is therefore? Options:
  A) 24.5 mole per dm³
  B) 0.2 mole per dm³
  C) 10.0 mole per dm³
  D) 20.0 mole per dm³
  E) 2.0 mole per dm³
  Show Answer
  The correct answer is E .
• Question 1220: Brass is an alloy containing copper and? Options:
  A) zinc
  B) tin
  C) aluminium
  D) silver
  E) lead
  Show Answer
  The correct answer is A .