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 1141: Elements X and Y have electronic configurations 1s²2s²2p⁶ and 1s²2s²2p⁶3s²3p¹ respectively. When they combine, the formula of the compound formed is Options:
  A) XY
  B) YX
  C) X₂Y₃
  D) Y₂X₃
  Show Answer
  The correct answer is D .
• Question 1142:

  In order to electroplate spoon with silver, the arrangement of the electrolytic cell is?

  Options:
  A) the anode is a silver rod and the cathode is the spoon
  B) the anode is the spoon and the cathode is a silver rod
  C) the electrolyte is silver trioxonitrate(v)( solution and the cathode is a silver rod.
  D) the electrolyte is silver trioxonitrate(v) solution and the anode is the spoon
  Show Answer
  The correct answer is A .
• Question 1143: If chlorine is bubbled into water and the resulting yellowish-green solution is exposed to bright sunlight for a while, the solution will decompose giving out Options:
  A) oxygen and leaving behind aqueous hydrochloric acid
  B) chlorine and oxygen
  C) oxygen, hydrogen and chlorine
  D) oxygen, thereby producing hypochlorous acid
  Show Answer
  The correct answer is A .
• Question 1144:

  Which of the following describes the chemical property of acids?

  Options:
  A) None of the above
  B) Acid + XCO${}_3$ $\to$ Salt + H${}_2$O + NH${}_3$
  C) Acid + NaOH $\to$ Normal salt + CO${}_2$
  D) Acid + X${}_n$CO${}_3$ $\to$ Salt + H${}_2$O + CO${}_2$
  Show Answer
  The correct answer is D .
• Question 1145: The bleaching action of chlorine gas is effective due to the presence of Options:
  A) hydrogen chloride
  B) water
  C) air
  D) oxygen
  Show Answer
  The correct answer is B .
• Question 1146: The general formula for the alkanals is Options:
  A) ROH
  B) R₂CO
  C) RCOOR¹
  D) RCHO
  Show Answer
  The correct answer is D .
• Question 1147:

  Which of the following metals is commonly alloyed with copper to make brass?

  Options:
  A) Iron
  B) Nickel
  C) Aluminum
  D) Zinc
  Show Answer
  The correct answer is D .
• Question 1148:

  H${}^{+}$ + OH${}^{-}$ H${}_2$O

  The equation above illustrates

  Options:
  A) precipitation
  B) hydration
  C) hydrolysis
  D) neutralization
  Show Answer
  The correct answer is D .
• Question 1149: What volume of 0.5 MH₂SO₄ will exactly neutralize 20cm³ of 0.1 MNaOH Solution? Options:
  A) 2.0cm³
  B) 5.0cm³
  C) 6.8cm³
  D) 8.3cm³
  Show Answer
  The correct answer is A .
• Question 1150: When temporary hard water is boiled for sometime in a kettle, the inner surface of the kettle becomes coated with a deposit of Options:
  A) calcium tetraoxosulphate(VI)
  B) calcium trioxocarbonate (IV)
  C) calcium hydrogentrioxocarbonate (IV)
  D) aluminium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .