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 1511:

  The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is

  Options:
  A) Na${}_2$SO${}_4$
  B) Na${}_2$SO${}_3$
  C) Na${}_2$S
  D) Na${}_2$CO${}_3$
  Show Answer
  The correct answer is B .
• Question 1512: Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid? Options:
  A) netralization with NaOHfoolowed by filtration
  B) neutralization with NaOH followed by distillation
  C) fractional distillation
  D) filtration followed by distillation
  Show Answer
  The correct answer is D .
• Question 1513: The equilibrium of an endothermic reaction which proceeds with an increase in volume can be shifted in the reverse direction by Options:
  A) increasing the temperature and decreasing the pressure
  B) increasing the pressure and increasing the temperature
  C) decreasing the temperature and increasing the pressure
  D) decreasing the pressure and decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 1514: Inspite of the electronic configuration, 1s²2s²2p², carbon is tetraavalent because? Options:
  A) the electrons in both 2s and 2p orbitals have equal energy
  B) the electrons in both 2s and 2p orbitals are equivalent
  C) both the 2s and 2p orbitals hybridizes
  D) the six orbitals hybridize to four
  Show Answer
  The correct answer is C .
• Question 1515: wH₂SO₄ + xAI(OH)₃ → yH₂O + = zAI₂(SO₄)₃. The respective values of w.x.y and z in the equation above are? Options:
  A) 2,2,5 and 1
  B) 3,2,5 and 2
  C) 3,2,6 and 1
  D) 2,2,6 and 2
  Show Answer
  The correct answer is C .
• Question 1516: The process that requires the use of hardwater in its operation is Options:
  A) Tanning
  B) Bottling
  C) Laundry
  D) Dyeing
  Show Answer
  The correct answer is B .
• Question 1517: The characteristics reaction of carbonyl compounds is? Options:
  A) substitution
  B) elimination
  C) addition
  D) saponfication
  Show Answer
  The correct answer is C .
• Question 1518:

  

  The oxidation of the compound above produces

  Options:
  A) 2-butanone
  B) 2-butanal
  C) 3-butanal
  D) 3-butanone
  Show Answer
  The correct answer is A .
• Question 1519: The air around a petroleum refinery is most likely to contain? Options:
  A) CO₂, SO₃ and N₂O
  B) CO₂, CO and N₂O
  C) SO₂, CO and NO₂
  D) PH₃ H₂O and CO₂
  Show Answer
  The correct answer is C .
• Question 1520: Consider the following equation H₂O + 2Fe²⁺ + Cl₂ ↔ 2Fe³⁺ + 2Cl^- + H₂O. The only ion which behaves as an oxidising agent is Options:
  A) Fe²⁺
  B) Cl₂
  C) Fe³⁺
  D) Cl^-
  E) H₂O
  Show Answer
  The correct answer is B .