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 2231:

  A correct electrochemical series can be obtained from Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

  Options:
  A) Al and Mg
  B) Zn and Fe
  C) Zn and Pb
  D) Pb and H
  Show Answer
  The correct answer is A .
• Question 2232: A saturated solution of AgCl was found to have a concentration of 1.30 x 10^-5 mol dm^-3. The solubility product of AgCl therefore is? Options:
  A) 1.30 x 10^-5 mol₂ dm^-6
  B) 1.30 x 10^-7 mol₂ dm^-6
  C) 1.69 x 10^-10 mol₂ dm^-6
  D) 2.60 x 10^-12 mol₂ dm^-6
  Show Answer
  The correct answer is C .
• Question 2233: Duralumin consists of aluminium, copper, ? Options:
  A) zinc and gold
  B) lead and maganese
  C) nickle and silver
  D) manganese and magnesium
  Show Answer
  The correct answer is D .
• Question 2234:

  Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.

  The process of loss is known as

  Options:
  A) efflorescence
  B) hygroscopy
  C) deliquescence
  D) effervescence
  E) dehydration
  Show Answer
  The correct answer is A .
• Question 2235: Which of the following is used in the manufacture of bleaching powder? Options:
  A) Sulphur dioxide
  B) Chlorine
  C) Hydrogen tetraoxosulphate (VI)
  D) Hydrogen sulphide
  E) Nitrogen dioxide
  Show Answer
  The correct answer is B .
• Question 2236: The process of converting starch to ethanol is Options:
  A) cracking
  B) distillation
  C) fermentation
  D) oxidation
  Show Answer
  The correct answer is C .
• Question 2237: Clothes should be properly rinsed with water after bleaching because? Options:
  A) the bleach decolourizes the cothes
  B) chlorine reacts with fabrics during bleaching
  C) the clothes are sterilized during bleaching
  D) hydrogen chloride solution is produced during bleaching
  Show Answer
  The correct answer is D .
• Question 2238:

  

  The set-up above would be useful for determining the amount of

  Options:
  A) oxygen in air
  B) water vapour in air
  C) CO₂ in air
  D) arygen in air
  Show Answer
  The correct answer is B .
• Question 2239:

  ²²⁶₈₈Ra → ^x₈₆Rn + α - particle

  What is the value of x in the nuclear reaction above?

  Options:
  A) 220
  B) 222
  C) 226
  D) 227
  Show Answer
  The correct answer is B .
• Question 2240: The oxidation state of oxygen in tetraoxosulphate (VI) acid is Options:
  A) -4
  B) -2
  C) +4
  D) -8
  Show Answer
  The correct answer is B .