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 391: A few drops of concentrated HNO₃ is added to an unknown solution and boiled for a while. If this produces a brown solution, the cation presents is likely to be Options:
  A) Pb²⁺
  B) Cu²⁺
  C) Fe³⁺
  D) Fe²⁺
  Show Answer
  The correct answer is D .
• Question 392: Which of the following is an electrolyte? Options:
  A) Alcohol
  B) Sodium acetate solution
  C) Solid potassium hydroxide
  D) Mercury
  Show Answer
  The correct answer is B .
• Question 393:

  If 100 cm³ of oxygen pass through a porous plug in 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is?

  (O = 16, H = 1)

  Options:
  A) 10.0 s
  B) 12.5 s
  C) 17.7 s
  D) 32.0 s
  Show Answer
  The correct answer is B .
• Question 394: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) Salt
  B) Dye
  C) Mordant
  D) Dispersant
  Show Answer
  The correct answer is C .
• Question 395:

  

  In the diagram above which of the cures illustrates Arrhenius' law?

  Options:
  A) Y
  B) Z
  C) R
  D) X
  Show Answer
  The correct answer is D .
• Question 396:

  The Consecutive members of an alkane homologous series differ by

  Options:
  A) CH
  B) CH${}_2$
  C) CH${}_3$
  D) C${}_n$H${}_n$
  Show Answer
  The correct answer is B .
• Question 397: Sodium carbonate crystals on exposure to a dry atmosphere change to a white powder. This phenomenon is known as? Options:
  A) deliquescence
  B) hygroscopy
  C) oxidation
  D) efforescence
  E) sublimation
  Show Answer
  The correct answer is D .
• Question 398: The alloy duralumin is used for the building of aeroplanes because it? Options:
  A) asborbs heat readily from sure thereby preventing the inside of the plane from getting cold at high attitudes
  B) reflects sunlight readily, thereby keeping the inside of the plane cool
  C) is extremely durable and possesses reflective ability
  D) is easily the lightest building material
  E) possesses both strenght and lightness
  Show Answer
  The correct answer is E .
• Question 399:

  What is the chemical name for the compound CuCO${}_3$?

  Options:
  A) Copper (iii) carbonate
  B) Copper (ii) carbonate
  C) Copper (i) carbonate
  D) Copper
  Show Answer
  The correct answer is B .
• Question 400: 2H₂S_(g) + SO_2(g) → 3S_(s) + 2H₂O_(I). The above reaction is? Options:
  A) a redox reaction H₂S is the oxidant and SO₂ is the reductant
  B) a redox reaction in which SO₂ is the oxidant and H₂S is the reductant
  C) not a redox reaction because there is no oxidant in reaction equation
  D) not a redox because there is no reductant in the reaction equation
  Show Answer
  The correct answer is B .