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 591:

  Which transition metal is known for its multiple colorful oxidation states and compounds used in pigments and paints?

  Options:
  A) Silver (Ag)
  B) Copper (Cu)
  C) Gold (Au)
  D) Zinc (Zn)
  Show Answer
  The correct answer is B .
• Question 592: The gas that is most useful in protecting humans against solar marathon is Options:
  A) chlorine
  B) ozone
  C) carbon IV oxide
  D) hydrogen sulphur
  Show Answer
  The correct answer is B .
• Question 593: 20.00 cm ³ of a solution containing 0.53 g of anhydrous Na₂CO₃ in 100 cm³ requires 25.00 cm³ of H₂SO₄ for complete neutralisation. The concentration of the acid solution in moles per dm is [H =1, C = 12, O = 16, Na =23, S = 32] Options:
  A) 0.02
  B) 0.04
  C) 0.06
  D) 0.08
  Show Answer
  The correct answer is B .
• Question 594: What type of bond exits between an element X with atomic number 12 and Y with atomic number 17? Options:
  A) Electrovalent
  B) Metallic
  C) Covalent
  D) Dative
  Show Answer
  The correct answer is A .
• Question 595:

  A concentrated solution containing H⁺, Cu²⁺, OH^- and Cl^- was electrolyzed using platinum electrodes.

  The ion that will be discharged at the cathode is

  Options:
  A) Cu²⁺
  B) Cl^-
  C) H⁺
  D) OH^-
  Show Answer
  The correct answer is A .
• Question 596:

  A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage

  Options:
  A) 11.%
  B) 22.2%
  C) 10%
  D) 20%
  Show Answer
  The correct answer is C .
• Question 597: The simplest branched-chain hydrocarbon is Options:
  A) ethane
  B) ethene
  C) propane
  D) butane
  Show Answer
  The correct answer is D .
• Question 598: An insoluble salt can be prepared by Options:
  A) the reaction of trioxocarbonate (V) with an acid
  B) double decomposition
  C) the action of dilute acid on an insoluble base
  D) the reaction of metals with an acid
  Show Answer
  The correct answer is B .
• Question 599: Alkanals can be distinguished from alkanones by the reaction with Options:
  A) sudan lll stain
  B) starch iodide paper
  C) lithium tetrahydrido aluminate (lll)
  D) fehling's solution
  Show Answer
  The correct answer is D .
• Question 600: Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond? Options:
  A) HF_(g)
  B) NH_3(g)
  C) CH_4(g)
  D) HCl_(g)
  Show Answer
  The correct answer is A .