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 1621: A carcinogenic substance is Options:
  A) asbestos dust
  B) sawdust
  C) nitrogen (II) oxide
  D) carbon (II) oxide
  Show Answer
  The correct answer is A .
• Question 1622:

  What is the PH of 0.00 1 moldm${}^3$ solution of the sodium hydroxide

  Options:
  A) 14
  B) 13
  C) 12
  D) 11
  Show Answer
  The correct answer is D .
• Question 1623:

  

  The above orbital diagram shown the electronic configuration of

  Options:
  A) chlorine
  B) nitrogen
  C) calcium
  D) neon
  Show Answer
  The correct answer is B .
• Question 1624:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  Options:
  A) 24,125 C
  B) 48,250 C
  C) 72,375 C
  D) 96,500 C
  Show Answer
  The correct answer is B .
• Question 1625: If an atom is represented as ${}_{11}^{23}X$, which of the following deduction is correct? Options:
  A) it contains 12 protonic
  B) it forms a covalent chloride
  C) its atomic number is 23
  D) it is an alkali metal
  Show Answer
  The correct answer is D .
• Question 1626: In which order are the following salts sensitive to light? Options:
  A) Agl > AgCl > AgBr
  B) AgCl > Agl > AgBr
  C) AgBr > AgCl > Agl
  D) AgCl > AgBr > Agl
  Show Answer
  The correct answer is D .
• Question 1627: Synthetic rubber is made by polymerization of? Options:
  A) 2 methyl buta - 1, 3 - diene
  B) 2 methyl buta - 1, 2 - diene
  C) 2 methyl but -1-ene
  D) 2 methyl but-2-ene
  Show Answer
  The correct answer is A .
• Question 1628: In the preparation of some pure crystals of Cu (NO₃)₂ starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ? Options:
  A) some CuO was reacted with excess dilute H₂SO₄
  B) the solution was concentrated
  C) when the concentrate was cooled, crystals formed were removed by filtration
  D) the crystals were washed with very little cold water
  E) the crystals were then allowed to dry
  Show Answer
  The correct answer is A .
• Question 1629: 60cm³ of hydrogen are sparked with 20cm³ of oxygen at 100°C and 1 atmosphere. The total volume of the residual gases is? Options:
  A) 60 cm³
  B) 10 cm³
  C) 40 cm³
  D) 30 cm³
  E) 70 cm³
  Show Answer
  The correct answer is A .
• Question 1630: In an electrolytic set-up to protect iron from corrosion, the iron is? Options:
  A) made cathode
  B) made anode
  C) used with a metal of lower electropositive potential
  D) initially coated with tin
  Show Answer
  The correct answer is D .