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 341:

  

  In the diagram above. X is

  Options:
  A) SO₃
  B) SO₂
  C) S
  D) H₂S
  Show Answer
  The correct answer is B .
• Question 342: If glucose is heated on the concentration tetraoxosulphate(iv)acid, it will be dehydrated Options:
  A) carbon
  B) carbon(iv)oxide
  C) ethane
  D) ethanol
  Show Answer
  The correct answer is A .
• Question 343: The best way of collecting chlorine is? Options:
  A) by downward displacement of air
  B) by upward displacement of air
  C) over water
  D) under water
  E) over mercury
  Show Answer
  The correct answer is B .
• Question 344: An elements X with relative atomic mass 16.2 contains two isotopes ¹⁶₈X with relative abundance of 90% and ^m₈X with relative abundance of 10%. The value of m is Options:
  A) 16
  B) 18
  C) 12
  D) 14
  Show Answer
  The correct answer is B .
• Question 345: An efflorescent compound is a substance that? Options:
  A) absorbs water froom the air without dissolving in it
  B) is capable of giving off coloured luminosity
  C) gives out water to the atmosphere
  D) absorbs water from the air and dissolves in it
  E) gives out its water of crystallization on heating
  Show Answer
  The correct answer is C .
• Question 346: The active reducing agent in the blast furnace for the extraction of iron is? Options:
  A) carbon
  B) limestone
  C) carbon(II)oxide
  D) calcium oxide
  Show Answer
  The correct answer is C .
• Question 347: Pollution of underground water by metal ions is very likely in the soil that has high Options:
  A) acidity
  B) alkalinity
  C) chloride content
  D) nitrate content
  Show Answer
  The correct answer is B .
• Question 348:

  How many pi ($\pi$) bonds are there in an alkene with six carbon atoms?

  Options:
  A) 4
  B) 6
  C) 5
  D) 3
  Show Answer
  The correct answer is D .
• Question 349: According to the kinetic theory, an increase in temperature causes the kinetic energy of particles to Options:
  A) Decrease
  B) Increase
  C) Remain constant
  D) Be zero
  Show Answer
  The correct answer is B .
• Question 350: 3Cl₂ + 2NH₃ $\to$ N₂ + 6HCl. In the above reaction, ammonia acts as Options:
  A) a reducing agent
  B) an oxidizing agent
  C) an acid
  D) a catalyst
  E) a dry agent
  Show Answer
  The correct answer is A .