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 331: When excess ethanol is heated to 145^oC in the presence of concentrated H₂SO₄, the product is Options:
  A) ethyne
  B) diethyl sulphate
  C) diethyl ether
  D) acetone
  Show Answer
  The correct answer is C .
• Question 332: Given that M is the mass of substance deposited in an electrolysis and Q the quantity of electricity consumed, then Faraday's law can be written as Options:
  A) M = Z/Q
  B) M = Q/Z
  C) M = Z/2Q
  D) M = QZ
  Show Answer
  The correct answer is D .
• Question 333: A pair of compounds that can be used to generate a gas which has physiological effect on human beings is Options:
  A) sodium trioxonitrate (V) and calcium chloride
  B) sodium dioxonitrate (III) and ammonium chloride
  C) sodium trioxonitrate (V) and ammonium chloride
  D) sodium dioxonitrate (III) and potassium chloride
  Show Answer
  The correct answer is A .
• Question 334:

  

  The diagram above represent the electron sub-level for

  Options:
  A) carbon
  B) nitrogen
  C) oxygen
  D) flourine
  Show Answer
  The correct answer is C .
• Question 335:

  Which of the following conditions will most enhance the spontaneity of a reaction?

  Options:
  A) $\mathrm{\Delta }$H is negative and greater than T$\mathrm{\Delta }$S
  B) $\mathrm{\Delta }$H is negative and $\mathrm{\Delta }$S = 0
  C) $\mathrm{\Delta }$H is positive and less than T$\mathrm{\Delta }$S
  D) $\mathrm{\Delta }$H is positive and equal to T$\mathrm{\Delta }$S
  Show Answer
  The correct answer is A .
• Question 336: Which of the following is NOT used as a raw material in the Solvay process? Options:
  A) Ammonia
  B) Sodium chloride
  C) Calcium trioxocarbonate (IV)
  D) Sodium trioxocarbonate (IV)
  Show Answer
  The correct answer is D .
• Question 337: Carbon (II) oxide is considered dangerous if inhaled mainly because it Options:
  A) can cause injury to the nervous system
  B) competes with oxygen in the blood
  C) competes with carbon (IV) oxide in the blood
  D) can cause lung cancer
  Show Answer
  The correct answer is B .
• Question 338: Chlorophyll obtained from given leaves of plant can be shown to be composed of more than one coloured component by the technique of Options:
  A) crystallization
  B) hydrolysis
  C) chromatography
  D) sublimation
  Show Answer
  The correct answer is C .
• Question 339:

  

  The diagram above best illustrates the effect of decrease in

  Options:
  A) concentration
  B) temperature
  C) surface area
  D) pressure
  Show Answer
  The correct answer is A .
• Question 340: Cathode rays causes an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays Options:
  A) are positively charged
  B) are negatively charged
  C) have mass
  D) travel in straight lines
  Show Answer
  The correct answer is D .