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 1031: 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 1032:

  An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

  Options:
  A) Alkene
  B) Alkanal
  C) Alkanone
  D) Alkanoic Acid
  Show Answer
  The correct answer is A .
• Question 1033:

  A sample of any of the following substances disappearsafter some time when exposed to air like camphor, naphthalene, or dry ice. This phenomenon is called?

  Options:
  A) Sublimation
  B) Evaporation
  C) Diffusion
  D) Radiation
  Show Answer
  The correct answer is A .
• Question 1034: Atomicity of ozone is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is C .
• Question 1035: The formula for ethyl butanoate is Options:
  A) C₃H₇COOC₂H₅
  B) C₂H₅COOC₃H₇
  C) C₄H₉COOC₂H₅
  D) C₂H₅COOC₄H₉
  Show Answer
  The correct answer is A .
• Question 1036: The oxidation number of boron in NaBH ₄ is Options:
  A) -3
  B) -1
  C) +1
  D) +3
  Show Answer
  The correct answer is D .
• Question 1037:

  Who proposed the planetary model of the atom with electrons orbiting the nucleus?

  Options:
  A) Erwin Schrödinger
  B) Ernest Rutherford
  C) Niels Bohr
  D) J.J. Thomson
  Show Answer
  The correct answer is C .
• Question 1038: Diffusion is slowest in solid particles than in particles of liquid and gases because Options:
  A) solid particles have more kinetic energy than the particles of liquid and gases
  B) solid particles have less kinetic energy than the particles of liqiud and gases
  C) solid particles have less restriction in their movement than liquid and gas particles
  D) the particles in solids are far apart and the cohesive forces between them are negligible
  Show Answer
  The correct answer is B .
• Question 1039: The nucleus of an atom contains Options:
  A) protons only
  B) neurons only
  C) protons and electrons
  D) neutrons and electrons
  E) protons and neutrons
  Show Answer
  The correct answer is E .
• Question 1040: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) Salt
  B) Dye
  C) Mordant
  D) Dispersant
  Show Answer
  The correct answer is C .