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: 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 392: Water for town supply is chlorinate to make it free from Options:
  A) bad colour
  B) bacteria
  C) temporary hardness
  D) permanent hardness
  Show Answer
  The correct answer is B .
• Question 393: When excess chlorine is mixed with ethene at room temperature, the product is Options:
  A) 1,2 - dichloroethane
  B) 1,2 - dichloroethene
  C) 1,1 - dichloroethane
  D) 1, 1 - dichloroethene
  Show Answer
  The correct answer is A .
• Question 394:

  What is Faraday's constant?

  Options:
  A) 6.022 x 10${}^{23}$ mol${}^{-1}$
  B) 3.00 x 10${}^8$ m/s
  C) 9.81 m/s${}^2$
  D) 96,485 C/mol
  Show Answer
  The correct answer is D .
• Question 395:

  Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V).
  [Ca = 40, N = 14, O = 16]

  Options:
  A) 8.5%
  B) 13.1%
  C) 17.1%
  D) 27.6%
  Show Answer
  The correct answer is C .
• Question 396:

  

  For which salt in the graph above does the solubility increase most rapidly with rise in temperature?

  Options:
  A) CaSO₄
  B) KNO₃
  C) NaCl
  D) KCl
  Show Answer
  The correct answer is B .
• Question 397:

  On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell

  Options:
  A) cu${}^{2+}$
  B) sn${}^{2+}$
  C) fe${}^{2+}$
  D) zn${}^{2+}$
  Show Answer
  The correct answer is A .
• Question 398: The tincture of iodine means iodine dissolved in Options:
  A) ethanol
  B) bromine chloride
  C) chlorine water
  D) water
  Show Answer
  The correct answer is A .
• Question 399:

  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 400: When chlorine gas is passed into a solution of sulphur dioxide? Options:
  A) sulphur dioxide is reduced to sulphur
  B) the chlorine is oxidized to hydrochloric acid
  C) dilute sulphuric acid and hydrochloric acid are produced
  D) Hydrochloric acid and sulphur are produced
  E) sulphur trioxide is the only product
  Show Answer
  The correct answer is C .