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 221: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attacks lead contained in pipes
  D) it encourage the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 222: When excess ethanol is heated to 145^oC in the presence of concentrated H₂SO₄, the product is Options:
  A) ethyne
  B) diethyl sulphate
  C) diethyl ether
  D) acetone
  Show Answer
  The correct answer is C .
• Question 223: A fixed mass of gas a volume of 92cm³ at 3°C. When will be its volume at 18C if the pressure remains constant? Options:
  A) 15.3cm³
  B) 87.3cm³
  C) 2.0cm³
  D) 97.0cm³
  Show Answer
  The correct answer is D .
• Question 224: Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys? Options:
  A) Tin
  B) Zinc
  C) Copper
  D) Lead
  E) Aluminium
  Show Answer
  The correct answer is C .
• Question 225: Na₂C₂O₄ + CaCl₂ → CaC₂O₄ + 2NaCl. Given a solution of 1.9g of sodium oxalate in 50g of water at room temperature, calculate the minimum volume of 0.1 M calcium oxalate using the above equation? Options:
  A) 1.40 χ 10² dm³
  B) 14.0 χ 10² cm³
  C) 1.40 χ 10^-2 dm^-2
  D) 14.0 χ 10^-2 cm³
  Show Answer
  The correct answer is A .
• Question 226: The salt formed from strong acid and a strong base is Options:
  A) complex
  B) neutral
  C) basic
  D) acidic
  Show Answer
  The correct answer is B .
• Question 227:

  NH₃ + H₃O⁺

  → NH₄⁺ + H₂O. It may be deduced from the reaction above that?

  Options:
  A) a redox reaction has occurred
  B) H₃O⁺ acts as an oxidizing agent
  C) H₃O⁺ acts as an acid
  D) water acts as ab acid
  Show Answer
  The correct answer is C .
• Question 228: The effect of the presence of impurities such as carbon and sulphur on iron is that they Options:
  A) give it high tensile strenght
  B) make it malleable and ductile
  C) increase its melting point
  D) lower its melting point
  Show Answer
  The correct answer is D .
• Question 229:

  

  The compound above exhibits

  Options:
  A) geometric isomerism
  B) optical isomerism
  C) structural isomerism
  D) positional isomerism
  Show Answer
  The correct answer is B .
• Question 230:

  A quantity of electricity liberates 3.6g of Silver from its salt. What mass of aluminium Will be liberated from its salt by the same quantity of electricity? [Al = 27, Ag = 108].

  Options:
  A) 2.7g
  B) 1.2g
  C) 0.9g
  D) 0.3g
  Show Answer
  The correct answer is A .