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 1001: Which of the following terms indicates the number of bonds that can be formed by an atom? Options:
  A) Oxidation number
  B) Valence
  C) Atomic number
  D) Electronegativity
  Show Answer
  The correct answer is B .
• Question 1002: What happens when zinc rod is immersed in copper (II) tetraoxosulphate (VI) solution/ Options:
  A) The blue colour of the solution disappears
  B) Electrons flow from copper to zinc
  C) The zinc rod remain undissolved
  D) The copper generate more copper ions
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  The correct answer is A .
• Question 1003:

  The lanthanides and actinides are located in which block of the periodic table?

  Options:
  A) P-block
  B) S-block
  C) F-block
  D) D-block
  Show Answer
  The correct answer is C .
• Question 1004:

  A chemical process in which there is a gain of electrons is known as?

  Options:
  A) Sublimation
  B) Reduction
  C) Oxidation
  D) Distillation
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  The correct answer is B .
• Question 1005:

  How many pi ($\pi$) bonds are there in an alkene with six carbon atoms?

  Options:
  A) 4
  B) 6
  C) 5
  D) 3
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  The correct answer is D .
• Question 1006:

  CH_4(g) + CI_2(g) $\to$ CH₂CI_(s) + HCI_g

  The major factor that influences the rate of the reaction above is

  Options:
  A) Concentration
  B) Catalyst
  C) Temperature
  D) Light
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  The correct answer is D .
• Question 1007: An emulsion paint consists of ? Options:
  A) gas or liquid particles dispersed in liguid
  B) liquid particles dispersed in liquid
  C) solid particles dispersed in liquid
  D) solid particles dispersed in solid
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  The correct answer is B .
• Question 1008: In the production of soap, concentrated sodium chloride solution is added to Options:
  A) increase the solubility of soap
  B) decrease the solubility of the soap
  C) saponify the soap
  D) emulsify the soap
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  The correct answer is B .
• Question 1009:

  Which functional group is present in alkanals?

  Options:
  A) Carbonyl group (C=O)
  B) Hydroxyl group (-OH)
  C) Alkyl group (-R)
  D) Carboxyl group (-COOH)
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  The correct answer is A .
• Question 1010:

  PCl_5(g) ↔ PCl_3(g) + Cl_2(g)

  In the reaction above, a decrease in pressure will

  Options:
  A) Decelerate the reaction
  B) Increase the yield of PCl₃
  C) Increase the yield of PCl₅
  D) Accelerate the reaction
  Show Answer
  The correct answer is B .