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 1211: The line observed in the sample hydrogen spectrum are due to emission of? Options:
  A) electrons from the atoms
  B) energy by proton transition
  C) energy by electron transition
  D) neutron from the atom
  Show Answer
  The correct answer is C .
• Question 1212:

  A colored gas that is known to be poisonous and can readily damage the mucous liningof the lungs is?

  Options:
  A) hydrogen sulphide
  B) carbon(ii)oxide
  C) chlorine
  D) sulphur(iv)oxide
  Show Answer
  The correct answer is C .
• Question 1213:

  The ions X_- and Y₊ are isoelectronic, each containing a total of 10 electrons.

  How many protons are in the nuclei of the neutral atoms of X and Y respectively?

  Options:
  A) 10 and 10
  B) 9 and 9
  C) 11 and 9
  D) 9 and 11
  Show Answer
  The correct answer is D .
• Question 1214: In which of the following is the oxidation number of sulphur equal to -2? Options:
  A) S₈
  B) H₂S
  C) SO ₂
  D) SO ₃^2-
  Show Answer
  The correct answer is B .
• Question 1215:

  

  Use the option above to answer this question. The structure of benzoic acid is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is D .
• Question 1216: During the vulcanization of rubber, sulphur is added to Options:
  A) Break down rubber polymer
  B) Lengthen the chain of rubber
  C) Bind rubber molecules together
  D) Act as a catalyst
  Show Answer
  The correct answer is C .
• Question 1217:

  Which of the following is an example of an endothermic reaction?

  Options:
  A) Combustion of propane (C${}_3$H${}_8$) to produce carbon dioxide (CO${}_2$) and water (H${}_2$O).
  B) Burning of methane (CH${}_4$) in the presence of oxygen
  C) Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl${}_2$).
  D) Decomposition of hydrogen peroxide (H${}_2$O${}_2$) into water (H${}_2$O) and oxygen (O${}_2$).
  Show Answer
  The correct answer is D .
• Question 1218: The purest from of iron which contains only about 0.1% carbon is Options:
  A) pig iron
  B) wrough iron
  C) cast iron
  D) iron pyrite
  Show Answer
  The correct answer is B .
• Question 1219: The alkanol obtained from the production of soap is Options:
  A) propanol
  B) ethanol
  C) glycerol
  D) methanol
  Show Answer
  The correct answer is C .
• Question 1220:

  

  The I.U.P.A.C name for the compound

  Options:
  A) 2-chloro-isopentane
  B) 3-chloro-isopentane
  C) 2-chloro-2-methylbutane
  D) 1-chloro-2,2- dimethylpropane
  E) 2-chloro-2-ethylpropane
  Show Answer
  The correct answer is C .