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 301: What is the correct IUPAC name for NO₂^-? Options:
  A) Dioxonitrate (IV) ion
  B) Trioxonitrate (III) ion
  C) Trioxonitrate (IV) ion
  D) Dioxonitrate (II) ion
  Show Answer
  The correct answer is D .
• Question 302:

  Cr₂O₇ + 6Fe²⁺ + 14H⁺ → 2Cr3+ + 6Fe³⁺ + 7H₂O. In the above, the oxidation number of chromium changed from?

  Options:
  A) +7 to +3
  B) +6 to +3
  C) +5 to +3
  D) -2 to +3
  Show Answer
  The correct answer is A .
• Question 303:

  Burning magnesium ribbon in air removes which of the following

  (i) oxygen (ii) nitrogen (iii) argon and (iv) carbon(iv)oxide?

  Options:
  A) i and iv only
  B) i, ii, iii and iv only
  C) i only
  D) i and ii only
  Show Answer
  The correct answer is C .
• Question 304:

  C_(s) + H₂O_(g) → H_2(g) + CO_2(g)

  ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

  Options:
  A) not feasible
  B) at equilibrium
  C) feasible
  D) exothermic
  Show Answer
  The correct answer is C .
• Question 305: In the preparation of carbon monoxide by heating ethanedioic acid with concentrated sulphuric acid, the concentrated sulphuric acid act as? Options:
  A) an oxidizing agent
  B) a reducing agent
  C) a dehydrating agent
  D) a reaction medium
  E) a catalyst
  Show Answer
  The correct answer is C .
• Question 306: What volume of 0.5 MH₂SO₄ will exactly neutralize 20cm³ of 0.1 MNaOH Solution? Options:
  A) 2.0cm³
  B) 5.0cm³
  C) 6.8cm³
  D) 8.3cm³
  Show Answer
  The correct answer is A .
• Question 307:

  3Cu + pHNO₃ →3Cu(NO)₂ + 4H₂ O + xNO

  In the equation above, the values of p and x respectively are

  Options:
  A) 1 and 3
  B) 2 and 3
  C) 6 and 2
  D) 8 and 2
  Show Answer
  The correct answer is D .
• Question 308: Which of the following are made by the process of polymerization? Options:
  A) Nylon and soap
  B) Nylon and artificial rubber
  C) Soap and butane
  D) Margarine and nylon
  Show Answer
  The correct answer is B .
• Question 309: Which of the following organic compounds is very soluble in water? Options:
  A) CH₃COOH
  B) C₂H₂
  C) C₂H₄
  D) CH₃COOC₂H₅
  Show Answer
  The correct answer is A .
• Question 310: The scale of a chemical balance is made of iron plate and coated with copper electrolytically because Options:
  A) iron is less susceptible to corrosion than copper
  B) copper is twice as less susceptitible to corrosion as iron
  C) copper is less susceptible to corrosion than iron
  D) copper and iron are equally susceptible to corrosion
  Show Answer
  The correct answer is C .