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 351: A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the? Options:
  A) iodide is oxidized
  B) tetraoxosulphate (Vl) acid acts as an oxidizing agent
  C) starch has been oxidized
  D) K₂Cr₂O₇ is oxidized
  Show Answer
  The correct answer is C .
• Question 352:

  A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

  Options:
  A) The solution is basic
  B) The solution is neutral
  C) The solution is acidic
  D) The litmus paper is faulty
  Show Answer
  The correct answer is C .
• Question 353:

  The ratio of the initial to the final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300cm${}^3$ at the same temperature.

  Options:
  A) 120cm${}^3$
  B) 200cm${}^3$
  C) 450cm${}^3$
  D) 750cm${}^3$
  Show Answer
  The correct answer is B .
• Question 354:

  What type of reaction is involved in the formation of alkanols from alkenes?

  Options:
  A) Elimination reaction
  B) Redox reaction
  C) Substitution reaction
  D) Addition reaction
  Show Answer
  The correct answer is D .
• Question 355: The IUPAC nomenclature of the compound LiAlH₄ is Options:
  A) lithiumtetrahydridoaluminate (III)
  B) aluminium tetrahydrido lithium
  C) tetrahydrido lithium aluminate (III)
  D) lithium aluminium hydride
  Show Answer
  The correct answer is A .
• Question 356: Four elements P,Q,R and S have 1,2,3, and 7 electrons in their outermost shells respectively. The element which is unlikely to be a metal is? Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is D .
• Question 357: The conversion of open chain alkanes into cycloalkanes and aromatic compounds is called Options:
  A) cracking
  B) reforming
  C) isomerization
  D) polymerization
  Show Answer
  The correct answer is B .
• Question 358:

  The hybridization in the compound $C{H}_3-C{H}_2-C\equiv H$ is

  Options:
  A) sp${}^3$ and sp
  B) sp
  C) sp${}^2$
  D) sp${}^3$ and sp${}^2$
  Show Answer
  The correct answer is A .
• Question 359: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 2.0 mole of Q ³⁺
  B) 2.5 mole of R²⁺
  C) 4.0 mole of Y^-
  D) 3.0 mole of T^-
  Show Answer
  The correct answer is A .
• Question 360: Reduction of nitroalkanes, nitrites and amides is a route for the preparation of Options:
  A) amines
  B) alkenes
  C) polymers
  D) detergents
  Show Answer
  The correct answer is A .