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 1261: The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore Options:
  A) none of these solutions is acidic
  B) the pH of Y is made more acidic by addition of distilled water
  C) Z is the most acidic solution
  D) W is the most acidic solution
  E) X is neutral
  Show Answer
  The correct answer is D .
• Question 1262: Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating? Options:
  A) Silver and trioxonitrate (V)
  B) Sodium trioxonitrate (V)
  C) Calcium trioxonitrate (V)
  D) Lithium trioxonitrate (V)
  Show Answer
  The correct answer is A .
• Question 1263: N₂O_4(g)→ 2NO_2(g)In the endothermic reaction above, more products formed will be favored by Options:
  A) A constant values
  B) an increase in pressure
  C) a decrease pressure
  D) a decrease volume
  Show Answer
  The correct answer is C .
• Question 1264: Which of the following silver halides is readily soluble in ammonium hydroxide? Options:
  A) Agl
  B) AgBr
  C) AgCl
  D) AgF
  E) None of the above
  Show Answer
  The correct answer is C .
• Question 1265: Which of the following processes takes place during electrolysis? Options:
  A) Positive ions are discharged at the anode bby gaining sufficient electrons to become neutral
  B) Negative ions are dicharged at the anode by gaining suficient electrons to become neutral
  C) Positive ions are discharged at the anode by losing sufficient electrons to become neutral
  D) Negative ions are discharge at the anode by losing sufficient electrons to become neutral
  E) Nothing happens
  Show Answer
  The correct answer is D .
• Question 1266: 2 - methyl propan -2- ol is an example of a Options:
  A) primary alkanol
  B) secondary alkanol
  C) tertiary alkanol
  D) quartenary alkanol
  Show Answer
  The correct answer is C .
• Question 1267:

  An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

  Reaction of X with yeast forms the basis of the

  Options:
  A) plastic industry
  B) textile industry
  C) brewing industry
  D) soap industry
  E) dyeing industry
  Show Answer
  The correct answer is C .
• Question 1268: Which of the following is a deliquescent compound? Options:
  A) Na₂CO₃
  B) CaCl₂
  C) CuO
  D) Na₂CO₃.10H₂O
  Show Answer
  The correct answer is B .
• Question 1269: What happens when zinc rod is immersed in copper (II) tetraoxosulphate (VI) solution/ Options:
  A) The blue colour of the solution disappears
  B) Electrons flow from copper to zinc
  C) The zinc rod remain undissolved
  D) The copper generate more copper ions
  Show Answer
  The correct answer is A .
• Question 1270: The iron (III) oxide impurity in bauxite can be removed by? Options:
  A) Fractional crystallization in acid solution
  B) dissolution in sodium hydroxide and filtration
  C) extraction with concentrated ammonia and reprecipitation
  D) electroysis of molten mixture
  Show Answer
  The correct answer is B .