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 1161: Cotton is almost pure? Options:
  A) starch
  B) protein
  C) animal fibre
  D) celluose
  E) mineral fibre
  Show Answer
  The correct answer is D .
• Question 1162: How many electrons are in the L shell of ³¹₁₅P? Options:
  A) 5
  B) 8
  C) 18
  D) 2
  Show Answer
  The correct answer is B .
• Question 1163: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 1164: The metal whose ore can be concentrated by passing it through a magnetic separator is Options:
  A) Zn
  B) Sn
  C) Cn
  D) Ca
  Show Answer
  The correct answer is B .
• Question 1165: If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ? Options:
  A) a drying agent
  B) an oxidizing agent
  C) a dehydrated agent
  D) a reducing agent
  E) a hydrolysing agent
  Show Answer
  The correct answer is C .
• Question 1166: The brown coloration in nitric acid prepared in the laboratory can be removed by? Options:
  A) heating the acid
  B) bubbling air through the acid
  C) cooling the acid
  D) adding a decolorizing agent
  E) adding a base
  Show Answer
  The correct answer is B .
• Question 1167:

  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 1168: How many lone pairs of electron are there on the central atom of the H₂O molecules? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 1169:

  A correct electrochemical series can be obtained from Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging

  Options:
  A) Al and Mg
  B) Zn and Fe
  C) Zn and Pb
  D) Pb and H
  Show Answer
  The correct answer is A .
• Question 1170:

  Which of the following does not support the fact that air is a mixture?

  Options:
  A) the constituents of air are in a fixed proportion by mass
  B) it cannot be represented with a chemical formula
  C) the constituents of air can be separated by physical by physical means
  D) none of the above
  Show Answer
  The correct answer is A .