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 631:

  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 632: The atom of an element X is represented as _z^yX. The basic chemical properties of X depends on the value of Options:
  A) Y
  B) Z
  C) Y - Z
  D) Z - Y
  Show Answer
  The correct answer is B .
• Question 633: An example of element that can catenate is Options:
  A) bromine
  B) nitrogen
  C) chlorine
  D) carbon
  Show Answer
  The correct answer is D .
• Question 634: Which of the following sulphides is insoluble in dilute HCl? Options:
  A) Na₂S
  B) ZnS
  C) CuS
  D) FeS
  Show Answer
  The correct answer is C .
• Question 635: If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is Options:
  A) metallic
  B) covalent
  C) co-ordinate
  D) ionic
  Show Answer
  The correct answer is D .
• Question 636: Which of these properties gives a solid its definite shape? Options:
  A) strong intermolecular attraction
  B) high melting point
  C) high boiling point
  D) weak intermolecular attraction
  Show Answer
  The correct answer is A .
• Question 637:

  In the reactions

  (I) H₂ (g) + 1/2O₂(g) → H₂O(l); ∆H = -286 KJ

  (II) C(s) + O₂g) → CO₂ (g); ∆H = -406 KJ the equations imply that

  Options:
  A) more heat is absorbed in (l)
  B) more heat is absorbed in (ll)
  C) less heat is evolved in (l)
  D) reaction (ll) proceeds faster than (l)
  E) reaction (l) proceeds faster than (ll)
  Show Answer
  The correct answer is C .
• Question 638: Aromatic and aliphatic hydrocarbons can be distinguished from each other by the? Options:
  A) action of bromine
  B) use of polymerization reaction
  C) action of heat
  D) use of oxidation reaction
  Show Answer
  The correct answer is C .
• Question 639:

  

  In the diagram above, mixture Y is

  Options:
  A) NH₄NO_3(s) + CaSO_4(s),/sub>
  B) NH₄CL_(s) + NaNO_2(s)
  C) NH₄NO_2(s) + Na₂SO_4(s)
  D) NH₄CL_(s) + Ca(OH)_2(s)
  Show Answer
  The correct answer is D .
• Question 640:

  

  2-methylbut-2-ene has the structure

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is D .