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 381: When at equilibrium, which of the reactions below will shift to the right if the pressure is increased and the temperature is kept constant? Options:
  A) 2SO_3(g) ↔ 2SO_2(g) + O_2(g)
  B) 2CO_2(g) ↔ 2CO_(g) + O_2(g)
  C) 2H_2(g) + O_2(g) ↔ 2H₂O_(g)
  D) 2NO_(g) ↔ N_2(g) + O_2(g)
  Show Answer
  The correct answer is C .
• Question 382: Farmlands affected by crude-oil spillage can be decontaminated by Options:
  A) Adding acidic solution
  B) Using aerobic bacteria
  C) Pouring water on the affected water area
  D) Burning off the oil from the area
  Show Answer
  The correct answer is B .
• Question 383: The process that requires the use of hardwater in its operation is Options:
  A) Tanning
  B) Bottling
  C) Laundry
  D) Dyeing
  Show Answer
  The correct answer is B .
• Question 384: The hydroxyl ion concentrated, (OH^-), in a solution of sodium hydroxide of pH 10.0 is? Options:
  A) 10^-10 mol dm^-3
  B) 10^-6 mol dm^-3
  C) 10^-4 mol dm^-3
  D) 10^-2 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 385:

  The following compounds are given with their corresponding boiling points.

  Compound Boiling Point

  i.................................14°C

  ii................................24°C

  iii................................0°C

  iv................................120°C

  V.................................-2°C

  From the above information, indicate which of the following is correct?

  Options:
  A) All the compounds are gaseous at 20 °C
  B) One of the compounds is gaseous at 20 °C
  C) Two of the compounds are gaseous at 20 °C
  D) Three of the compounds are gaseous at 20 °C
  E) None of the compounds is gaseous at 20 °C
  Show Answer
  The correct answer is D .
• Question 386: Which of the following compounds can be represented by the molecular formula C2 H6O? Options:
  A) propanal
  B) ethanol
  C) methanoic acid
  D) glucose
  Show Answer
  The correct answer is B .
• Question 387: Which of the following happens during the electrolysis of molten sodium chloride? Options:
  A) Sodium ion loses an electron
  B) Chlorine atom gains an electron
  C) Chlorine ion gains an electron
  D) Sodium ion is oxidized
  E) Chloride ion is oxidized
  Show Answer
  The correct answer is E .
• Question 388: The ideal gas laws and equations are true for all gases at Options:
  A) low pressures and lower temperatures
  B) low temperatures and high pressures
  C) high pressures and high temperatures
  D) low pressure and high temperatures
  Show Answer
  The correct answer is D .
• Question 389: Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume? Options:
  A) 91K
  B) 182K
  C) 273K
  D) 819K
  Show Answer
  The correct answer is A .
• Question 390:

  The sub-atomic particles located in the nucleus of an atomare?

  Options:
  A) neutron and proton
  B) proton and electron
  C) proton and ions
  D) neutron and electron
  Show Answer
  The correct answer is A .