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 171:

  A solution X on mixing with AgNO₃ solution, gives a white precipitate solution in NH₃. A Solution Y, when added to X, also gives a white precipiate which is soluble on boiling. Solution Y contains?

  Options:
  A) Ag⁺ ion
  B) Pb²⁺ ion
  C) Pb⁴⁺ ion
  D) Zn²⁺ ion
  E) Al³⁺ ion
  Show Answer
  The correct answer is B .
• Question 172: For the reaction 2Fe³⁺ 2I^- $\to$ 2Fe²⁺ + I₂, which of the following statements is TRUE? Options:
  A) Fe is oxidized to Fe³⁺
  B) Fe³⁺ is oxidized to Fe²⁺
  C) I^- is oxidized to I₂
  D) I^- is reduced to I₂
  E) I^- is displacing an electron from Fe³⁺
  Show Answer
  The correct answer is C .
• Question 173:

  What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

  Options:
  A) 10cm${}^3$
  B) 12cm${}^3$
  C) 14cm${}^3$
  D) 16cm${}^3$
  Show Answer
  The correct answer is D .
• Question 174: How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?(Ni = 58.7, 1F = 96 500 C mol^-) Options:
  A) 0.20
  B) 0.30
  C) 0.40
  D) 0.50
  Show Answer
  The correct answer is C .
• Question 175: Sodium chloride has no solubility product value because of its? Options:
  A) saline nature
  B) high solubility
  C) low solubility
  D) insolubility
  Show Answer
  The correct answer is B .
• Question 176: The electronic configuration of an elements is 1s²2s²2p⁶3s²3p³. How many unpaired electrons are there in the element? Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is C .
• Question 177: An example of an alcohol is Options:
  A) CCl₄
  B) CH₃COOH
  C) CHCl₃
  D) C₂H₆
  E) CH₃OH
  Show Answer
  The correct answer is E .
• Question 178: Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises? Options:
  A) The bonds in the reacting molecules are more readily broken
  B) The molecular collisions become more violent
  C) A lower proportion of the molecules has the necessary minimum energy to react
  D) The collision frequency of the molecules increase
  Show Answer
  The correct answer is D .
• Question 179: A solution of calcium bromide contains 20 g dm ³ What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80] Options:
  A) 0. 1, 0 . 1
  B) 0. 1, 0. 2
  C) 0. 1, 0. 05
  D) 0.05, 0.1
  Show Answer
  The correct answer is C .
• Question 180: Sucrose is made up of Options:
  A) glucose and glucose
  B) glucose and fructose
  C) fructose and fructose
  D) galactose and glucose
  Show Answer
  The correct answer is B .