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 811: Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because Options:
  A) zinx is not rendered passive by acid
  B) hydrogen produced is oxidized to water
  C) oxides of nitrogen are produced
  D) all nitrates are soluble in water
  E) trioxonitrate(v)acid is a strong acid
  Show Answer
  The correct answer is E .
• Question 812:

  A synthetic rubber is obtained from the polymerization of

  Options:
  A) neoprene
  B) isoprene
  C) butandiene
  D) propylene
  Show Answer
  The correct answer is B .
• Question 813: Coal fire should not be used in poorly ventilated rooms because ? Options:
  A) of the accumulation of CO₂ which causes dep sleep
  B) it is usually too hot
  C) of the acumulation of CO which causes suffocation
  D) it removes most most of the gases in the rooms
  Show Answer
  The correct answer is C .
• Question 814:

  The process by which salt and water reacted in a limited way to form an acid or abase is?

  Options:
  A) Neutral process
  B) Basic acidic process
  C) Hydrolysis
  D) Sublimation
  Show Answer
  The correct answer is C .
• Question 815:

  Methane is prepared in the laboratory by heating a mixture of sodium ethanoate with soda lime. The chemical constituent(s) of soda lime is/are

  Options:
  A) Ca(OH)${}_2$ and NaOH
  B) Na${}_2$CO${}_3$
  C) NaCl
  D) NaOH
  Show Answer
  The correct answer is A .
• Question 816: A mixture of sugar and sulphur can be separated by Options:
  A) dissolution in water, evapouration and filtration
  B) filtration, evaporation and dissolution in water
  C) dissolution in water, filtration and evaporation
  D) evaporation, dissolution in water and filtration
  Show Answer
  The correct answer is C .
• Question 817:

  Which of the following metals is commonly alloyed with copper to make brass?

  Options:
  A) Iron
  B) Nickel
  C) Aluminum
  D) Zinc
  Show Answer
  The correct answer is D .
• Question 818: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 819:

  An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

  Compound W is

  Options:
  A) a soap
  B) an oil
  C) an alkane
  D) an ester
  E) sucrose
  Show Answer
  The correct answer is D .
• Question 820: X_(g) + 3Y_(g) ---- 2z_(g) H = +ve. if the reaction above takes place at room temperature, the G will be Options:
  A) negative
  B) zero
  C) positive
  D) indeterminate
  Show Answer
  The correct answer is D .