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 2271: In titration involving sodium hydroxide and dilute hydrochloric acid, where would you place the base? Options:
  A) in the beaker
  B) in the conical flask
  C) in a burette
  D) in the standard flask
  E) in the measuring cylinder
  Show Answer
  The correct answer is B .
• Question 2272:

  How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = 6.02 x 10 ${}^{23}$mol]

  Options:
  A) 1.20 x 10${}^{22}$
  B) 2.4 x 10${}^{22}$
  C) 1.51 x 10${}^{22}$
  D) 3.02 x 10${}^{22}$
  Show Answer
  The correct answer is C .
• Question 2273: Complete hydrogenation of ethyne yields? Options:
  A) benzene
  B) methane
  C) ethane
  D) ethene
  E) propane
  Show Answer
  The correct answer is C .
• Question 2274: 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 .
• Question 2275:

  

  Choose the correct answer from the options above.

  When Fehling's solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C ₅H ₁₀O, compound X gives a red precipitate while Y does not react. It can be inferred that X is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 2276:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 2277:

  C₁₂H₂₂O_11(s) + H₂SO_4(aq) 12C_(s) + 11H₂O_(l) + H₂SO_4(aq)

  In the reaction above, tetraoxosulphate (VI) acid function as

  Options:
  A) A dehydrate agent
  B) An oxidizing agent
  C) A reducing agent
  D) A catalyst
  Show Answer
  The correct answer is A .
• Question 2278: In the experiment, which of the following observations would suggest that a solid sample is a mixture? The Options:
  A) solid can be ground to a fine powder
  B) density of the solid is 2.25gdm^-3
  C) solid begins to melt at 573k but is not completely melted until 648k
  D) solid absorbs moisture from the atmosphere and turns into liquid
  E) solid melts at 300k
  Show Answer
  The correct answer is C .
• Question 2279:

  The general formula of alkanoates is?

  Options:
  A) $RCHO$
  B) $R_{2}CO$
  C) $RCOOH$
  D) $RCOO{R}^{\prime }$
  Show Answer
  The correct answer is D .
• Question 2280: The property used in obtaining oxygen and nitrogen industrially from air is the? Options:
  A) boiling point
  B) density
  C) rate of diffusion
  D) solubility
  Show Answer
  The correct answer is A .