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 2031: The repeating unit in natural rubber is Options:
  A) alkyne
  B) isoprene
  C) n-propene
  D) peoprene
  Show Answer
  The correct answer is B .
• Question 2032: Chlorination of water for town supply is carried out to Options:
  A) make the water colourless
  B) remove germs from the water
  C) make the water tastedful
  D) remove odour from the water
  Show Answer
  The correct answer is B .
• Question 2033:

  

  An experiment test of the Law of conservation of Mass is illustrated in the diagram. In practice, the flask is weighed before and after reaction between solutions X and Y. Which of the following pairs of solutions will be unsuitable for the experiments

  Options:
  A) X = hydrochloric acid; Y = silver nitrate
  B) X = barium chloride; Y = dilute sulphuric acid
  C) X = hydrochloric acid; Y = sodium hydroxide
  D) X = hydrochloric acid; Y = lead nitrate
  E) X = hydrochloric acid; Y = sodium carbonate
  Show Answer
  The correct answer is E .
• Question 2034: CaO_s + H₂O_(l) → Ca(OH)_2(s) ΔH -65 kj. The process represented by the above equation is known as? Options:
  A) dissolution
  B) slaking
  C) liming
  D) mortaring
  Show Answer
  The correct answer is B .
• Question 2035: When chlorine Is passed into water and the resulting solution exposed to sunlight, the product formed are Options:
  A) Chlorine gas and hydrogen
  B) Oxygen and oxochlorate (I) acid
  C) Chlorine gas and oxochlorate (I) acid
  D) Hydrochloric acid and oxygen
  Show Answer
  The correct answer is D .
• Question 2036: CO_g + H₂O_g $\to$ _2g + H_2g $\mathrm{\Delta }$H = -4100J. Which of the following factors favour the formation of hydrogen in the above reaction? i. high pressure. ii. low pressure iii. high temperature iv. use of excess steam Options:
  A) i, iii and iv
  B) iii only
  C) ii, iii and i
  D) iv only
  Show Answer
  The correct answer is D .
• Question 2037: The acid used in electrolysis of water is dilute Options:
  A) HNO₃
  B) CH₃COOH
  C) H₂SO₄
  D) HCl
  Show Answer
  The correct answer is C .
• Question 2038: 2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is? Options:
  A) 200 g
  B) 160 g
  C) 100 g
  D) 50 g
  Show Answer
  The correct answer is C .
• Question 2039: Calcium tetraoxosulphate (VI) dissolves in water only sparingly to form a Options:
  A) solution
  B) suspension
  C) precipitate
  D) colloid
  Show Answer
  The correct answer is C .
• Question 2040: The atomic radius of Li, Na and K are 1: 33A, 1. 54A and 1. 96A res pectively. Which of the following explaqins this gradation in atomic radius? Options:
  A) electropositivity decreases from Li to Na to K
  B) electronegativity decreases from Li to Na to K
  C) the number of the electron shells increases from Li to Na to K
  D) the elements are in the same period
  Show Answer
  The correct answer is C .