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 381:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 382: Which of the following types of reactions takes place between C₂H₄ and the halogens? Options:
  A) Substitution
  B) Polymerization
  C) Addition
  D) Saponification
  E) Oxidation
  Show Answer
  The correct answer is C .
• Question 383:

  At 27°C, 58.5g of sodium chloride is present in 250cm${}^3$ of a solution. The solubility of sodium chloride at this temperature is?

  (molar mass of sodium chloride = 111.0gmol${}^{-1}$)

  Options:
  A) 2.0 moldm${}^{-3}$
  B) 0.25 moldm${}^{-3}$
  C) 1.0 moldm${}^{-3}$
  D) 0.5 moldm${}^{-3}$
  Show Answer
  The correct answer is A .
• Question 384:

  CO_(g) + H₂ O_(g) → CO_2(g) + H_2(g)

  Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) and CO_(g) in KJ mol ^-1 are - 394 -242 and - 110 respectively.

  Options:
  A) + 262 KJ mol ^-1
  B) - 262 KJ mol ^-1
  C) + 42 KJ mol ^-1
  D) - 42 KJ mol ^-1
  Show Answer
  The correct answer is D .
• Question 385:

  The heat of formation of ethene, C${}_2$H${}_4$ is 50 kJmol${}^{-1}$, and that of ethane, C${}_2$H${}_6$ is -82kJmol${}^{-1}$. Calculate the heat evolved in the process:

  C${}_2$H${}_4$ + H${}_2$ $\to$ C${}_2$H${}_6$

  Options:
  A) -122kJ
  B) -132kJ
  C) -88kJ
  D) -60kJ
  Show Answer
  The correct answer is B .
• Question 386: In the electrolytic extraction of cacium from calcium chloride, the cathode is Options:
  A) zinc
  B) graphite
  C) platinum
  D) iron
  Show Answer
  The correct answer is D .
• Question 387:

  What current will deposit 3.25g of zinc in 2hrs?

  [Zn = 65, F = 96500 mol^-]

  Options:
  A) 3.25A
  B) 2.00A
  C) 1.34A
  D) 0.67A
  Show Answer
  The correct answer is C .
• Question 388:

  The Consecutive members of an alkane homologous series differ by

  Options:
  A) CH
  B) CH${}_2$
  C) CH${}_3$
  D) C${}_n$H${}_n$
  Show Answer
  The correct answer is B .
• Question 389:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 390:

  

  The compound above is

  Options:
  A) glycol
  B) primary alkanol
  C) secondary alkanol
  D) tertiary alkanol
  Show Answer
  The correct answer is C .