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 1541:

  

  The above orbital diagram shown the electronic configuration of

  Options:
  A) chlorine
  B) nitrogen
  C) calcium
  D) neon
  Show Answer
  The correct answer is B .
• Question 1542:

  

  Use the diagram above to answer this question.

  The reaction taking place in the flask above is known as

  Options:
  A) hydrolysis
  B) double decomposition
  C) dehydration
  D) pyrolysis
  Show Answer
  The correct answer is C .
• Question 1543: An acid and its conjugate base Options:
  A) can neutralise each other to form a salt
  B) differ only by a proton
  C) differ only by the opposite charges they carry
  D) are always neutral substances
  Show Answer
  The correct answer is B .
• Question 1544: Which of the following solutions will give a white precipitate with barium chloride solution and a green flame test? Options:
  A) Na₂SO₄
  B) CuSO₄
  C) CaSO₄
  D) CaCI₂
  E) (NH₄)₂SO₄
  Show Answer
  The correct answer is B .
• Question 1545: When few drops of concentrated trioxonitrate(V) acid is added to an unknown sample and wanned an intense yellow colouration is observed. The likely functional group present in the sample is Options:
  A) NH₃—C—C=O
  B) CHO
  C) CO
  D) CNH₂
  Show Answer
  The correct answer is A .
• Question 1546: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) Salt
  B) Dye
  C) Mordant
  D) Dispersant
  Show Answer
  The correct answer is C .
• Question 1547: The fuming of kettles is caused by the presence in the water of Options:
  A) Calcium tetraoxosulphate (VI)
  B) Calcium hydrogentrioxocarbonate (IV)
  C) Calcium hydroxide
  D) Calcium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 1548:

  A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as __________.

  Options:
  A) an acidic oxide
  B) a basic oxide
  C) a neutral oxide
  D) an amphoteric oxide
  Show Answer
  The correct answer is D .
• Question 1549: If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because Options:
  A) both zinc and copper are metals
  B) the sulphate radical and the zinc ion are divalent
  C) zinc is more electropositive than copper
  D) both zinc and copper form depositive ions in solution
  E) zinc is a reducing agent
  Show Answer
  The correct answer is C .
• Question 1550: The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): $\mathrm{\Delta }$H =46.0 kJ is Options:
  A) isothermic
  B) adiabatic
  C) isobaric
  D) endothermic
  E) exothermic
  Show Answer
  The correct answer is D .