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 1551:

  X is a substance which liberates CO${}_2$ on treatment with concentrated H${}_2$SO${}_4$. A warm solution of X can decolorize acidified KMnO${}_4$. X is

  Options:
  A) HCOOH
  B) NaHCO${}_3$
  C) FeCO${}_3$
  D) H${}_2$C${}_2$O${}_4$
  Show Answer
  The correct answer is D .
• Question 1552:

  Zn_(s) + CuSO_4(aq) $\to$ ZnSO_4(aq) + Cu_(s)

  In the reaction above, the oxidizing agent is

  Options:
  A) CuSO_4(aq)
  B) ZnSO_4(aq)
  C) Cu_(s)
  D) Zn_(s)
  Show Answer
  The correct answer is A .
• Question 1553:

  

  In the diagram above, the gas produced is

  Options:
  A) NO
  B) NO₂
  C) N₂O
  D) N₂O₄
  Show Answer
  The correct answer is A .
• Question 1554: Which of the reactions occurs at the anode during the electrolysis of a very dilute aqueous solution of sodium chloride? Options:
  A) OH^- - e → OH
  B) CIsup>- - e → CI
  C) OHsup>- + CIsup>-HCI + O₂
  D) Na₊ - esup>- Hg (Na)/(Hg) amalgam
  Show Answer
  The correct answer is A .
• Question 1555: H ₂O _(g) + C _(s) → H_2(g) + CO_(g)The oxidizing agent in the reaction above is Options:
  A) CO_(g)
  B) C_(s)
  C) H₂O_(g)
  D) H_(2)(g)
  Show Answer
  The correct answer is C .
• Question 1556: A man suspected of being drunk is made to pass his breath into acidified potassium dichlormate solution. If his breath carries a significant level of ethanol, the final colour of the solution is? Options:
  A) pink
  B) purple
  C) orange
  D) blue-black
  E) green
  Show Answer
  The correct answer is E .
• Question 1557: To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of Options:
  A) CO^-
  B) Cl^-
  C) SO^-
  D) NO
  Show Answer
  The correct answer is D .
• Question 1558: If y is an oxidizing agent that reacts with a reducing agent, Z, which of the following is correct? Options:
  A) Y increases in oxidation number
  B) Y becomes reduced
  C) Z loses protons
  D) Z gains protons
  Show Answer
  The correct answer is B .
• Question 1559:

  C₂H₅OH_(aq) → Y

  If the above reaction takes place in conc. H₂SO₄ at 180^o, Y represents

  Options:
  A) CH₄
  B) C₂H₅COOH
  C) C₂H₄
  D) CH₃OCH₃
  Show Answer
  The correct answer is C .
• Question 1560: The filter in the cigarette reduces the nicotine content by Options:
  A) Burning
  B) Adsorption
  C) Evaporation
  D) Absorption
  Show Answer
  The correct answer is B .