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 1251: Which of the following oxides of nitrogen is unstable in air? Options:
  A) NO₂
  B) NO
  C) N₂O₄
  D) N₂O_5-
  Show Answer
  The correct answer is B .
• Question 1252:

  At 25^o and zymase as catalyst,

  C₆H₁₂₆ → 2C₂H₅OH + 2CO₂ + energy

  The reaction above represented by the equation above is useful in the production of

  Options:
  A) propanol
  B) butanol
  C) methanol
  D) ethanol
  Show Answer
  The correct answer is D .
• Question 1253: 12 g of solid protassium chlorate (KCIO) were added to 40 g of water and heated to dissolve all the solid. As the solution cools, crystals of potassium chlorate at 66 ^oC. The solubility of potassium chlorate at 66 ^oC is therefore Options:
  A) 66
  B) 33
  C) 10
  D) 20
  E) 30
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  The correct answer is E .
• Question 1254:

  Elements in the periodic table are arranged in the order of their

  Options:
  A) atomic numbers
  B) metallic character
  C) mass number
  D) relative atomic mass
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  The correct answer is A .
• Question 1255:

  Suitable reagents for the laboratory preparation nitrogen are

  Options:
  A) sodium dioxonitrate(III) and ammonium chloride
  B) sodium trioxonitrate(V) and ammonium chloride
  C) sodium chloride and ammonium trioxonitrate(V)
  D) sodium chloride and ammonium di-ozonitrate(III)
  Show Answer
  The correct answer is A .
• Question 1256:

  Hydrocarbons which will react with Tollen's reagent conform to the general formula

  Options:
  A) C${}_n$H${}_{2n}$
  B) C${}_n$H${}_{2n+2}$
  C) C${}_n$H${}_{2n-2}$
  D) C${}_n$H${}_{2n+1}$OH
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  The correct answer is C .
• Question 1257:

  The sub-atomic particles located in the nucleus of an atomare?

  Options:
  A) neutron and proton
  B) proton and electron
  C) proton and ions
  D) neutron and electron
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  The correct answer is A .
• Question 1258:

  

  The compound above exhibits

  Options:
  A) Geometric isomerism
  B) Positional isomerism
  C) Structural isomerism
  D) Optical isomerism
  Show Answer
  The correct answer is D .
• Question 1259:

  When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?

  Options:
  A) Bipolar
  B) Negatively charged
  C) Positively charged
  D) Neutral
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  The correct answer is B .
• Question 1260:

  When a substance is oxidized, it

  Options:
  A) Loses electrons
  B) Gains oxygen atoms
  C) Gains electrons
  D) Loses protons (H+ ions)
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  The correct answer is A .