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 91: A suitable reagent for distinguishing between ethanoic acid ethanol is Options:
  A) bromine water
  B) Fehling's solution
  C) sodium hydrogentrioxocarbonate (IV)
  D) ammoniacal silver trioxonitrate (V)
  Show Answer
  The correct answer is C .
• Question 92: Deliquescent substances are also? Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 93: The oxidation number of boron in NaBH ₄ is Options:
  A) -3
  B) -1
  C) +1
  D) +3
  Show Answer
  The correct answer is D .
• Question 94: A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a Options:
  A) trioxonitrate (V)
  B) chloride
  C) trioxocarbonate (IV)
  D) hydroxide
  Show Answer
  The correct answer is C .
• Question 95: In the extraction of iron, the waste gas from the furnace is a mixture of Options:
  A) PH₃ CO and CO₂
  B) CO and C
  C) N₂ CO and CO₂
  D) PH₃ and CO
  Show Answer
  The correct answer is A .
• Question 96:

  Isotopes of an element have

  Options:
  A) The same number of protons but different numbers of neutrons.
  B) The same number of neutrons and electrons
  C) The same number of protons and neutrons
  D) The same number of protons and electrons
  Show Answer
  The correct answer is A .
• Question 97:

  CO_(g) + H₂O_(g) → CO_2(g) + H_2(g)

  From the reaction above, calculate the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) in kJ mol^-1 are -394, -242, and -110 respectively.

  Options:
  A) -262 kJ mol^-1
  B) -42 kJ mol^-1
  C) +42 kJ mol^-1
  D) +262 kJ mol^-1
  Show Answer
  The correct answer is B .
• Question 98:

  32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm${}^3$ of water generated 13.0kj of heat. The heat solution is?

  Options:
  A) 26.0kj/mol
  B) 65.0kj/mol
  C) 130.0kj/mol
  D) 260.0kj/mol
  Show Answer
  The correct answer is B .
• Question 99: Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.Which of the above are NOT typical properties of alkalis? Options:
  A) i, iv and v
  B) iv and v
  C) i and iv
  D) ii and v
  E) ii, iii and iv
  Show Answer
  The correct answer is C .
• Question 100: Ca(OH)_2(s) + 2NH₄Cl_(g) → CaCl_2(s) + 2H₂O_2(l) + X. In the reaction above X is Options:
  A) NO₂
  B) NH₃
  C) N₂O
  D) NO₂
  Show Answer
  The correct answer is B .