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 521: Phenolphthalein in acidic solution is Options:
  A) red
  B) orange
  C) colourless
  D) yellow
  Show Answer
  The correct answer is C .
• Question 522: The product formed at the the cathode during the electrolysis of sodium chloride solution with carbon electrodes is? Options:
  A) sodium
  B) chlorine
  C) hydrogen
  D) sodium hydroxide
  E) oxygen
  Show Answer
  The correct answer is C .
• Question 523: The nitrogen obtained from air has a density higher than the one from nitrogen-containing compounds because the one from air is contaminated with Options:
  A) water vapour
  B) oxgyen
  C) rare gases
  D) carbon (IV) oxide
  Show Answer
  The correct answer is C .
• Question 524: 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 525: The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an? Options:
  A) alkanoate
  B) alkaene
  C) alkanol
  D) alkane
  Show Answer
  The correct answer is C .
• Question 526: A metal is extracted from its ore by the electrolysis of its molten chloride and it displaces lead from lead (ll) trioxonitrate (V) solution. The metal is Options:
  A) copper
  B) aluminium
  C) zinc
  D) sodium
  Show Answer
  The correct answer is D .
• Question 527: The solubilites of different solutes in a given solvent can be compared by Options:
  A) plotting their solubility curves on separete axes
  B) plotting their solubility curves on the same axes
  C) plotting some of the solubility curves on the x-axis and others on the y-axis
  D) plotting their solubility curves on the x-axis only
  Show Answer
  The correct answer is B .
• Question 528: Helium is often used in observation balloons because it is? Options:
  A) light and combustible
  B) light and non-combustible
  C) heavy and combustible
  D) heavy and non-combustible
  Show Answer
  The correct answer is B .
• Question 529:

  An organic compound with fishy smell is likely to have a general formula?

  Options:
  A) RCONHR${}^1$
  B) RCONH${}_2$
  C) RNH${}_2$
  D) RCOR${}^1$
  Show Answer
  The correct answer is C .
• Question 530: Na₂C₂O₄ + CaCl₂ → CaC₂O₄ + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation? Options:
  A) 1.40 χ 10² dm³
  B) 14.0 χ 10² cm³
  C) 1.40 χ 10^-2 dm^-2
  D) 14.0 χ 10^-2 cm³
  Show Answer
  The correct answer is A .