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 2211: Which of the following ions will give a white precipitate with aqueous NaOH and soluble in excess of the base? Options:
  A) Ca²⁺
  B) Mg²⁺
  C) Zn²⁺
  D) Cu²⁺
  Show Answer
  The correct answer is C .
• Question 2212: The four classes of hydrocarbons are? Options:
  A) ethane, ethene, ethyne and benzene
  B) alkanes, alkenes, alkynes and aromatics
  C) alkanes, alkenes, alkynes and benzene
  D) methane, ethane , propane and butane
  Show Answer
  The correct answer is B .
• Question 2213: A hydrated salt of formula MSO₄.xH₂ O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ] Options:
  A) 3
  B) 5
  C) 7
  D) 10
  Show Answer
  The correct answer is C .
• Question 2214:

  A sample of a substance containing only C and H burns in excess O₂ to yield 4.4g of CO₂

  And 2.7 g of H₂O. The empirical formula of a substance is?(C = 12, O = 16, H = 1)

  Options:
  A) CH₃
  B) CH₂
  C) CH₄
  D) C₂H₂₄
  Show Answer
  The correct answer is A .
• Question 2215:

  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 2216: Which of the following statements is INCORRECT?
  Options:
  A) Fractional distillation of crude petroleum will give the folloing hydrocarbon fuels in order of increasing boiling point
  B) Butane < petrol < kerosene of polythene.
  C) Both but-1-ene and but-1-yne will decolorize bromine readily
  D) but-2-ene will react with chlorine to form 2,3-dichlorobutane
  E) calcuim carbide will react with water to form any alkyne
  Show Answer
  The correct answer is E .
• Question 2217:

  2X_(aq) + MnO_2(s) + 4H⁺_(aq) → X_2(g) + Mn²⁺_(aq) + 2H₂O.

  The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

  Options:
  A) a poisionous gas
  B) an oxidizing agent
  C) electronegative in nature
  D) highly reactive
  Show Answer
  The correct answer is D .
• Question 2218:

  1.1 g of CaCI₂ dissolved in 50 cm³ of water caused a rise in temperature of3.4°C. The heat of reaction, ∆H for CaCI₂ in kj per mole is?

  (Ca = 40, CI = 35.5, specific heat of water is 4.18 jk^-1

  Options:
  A) -71.1
  B) -4.18
  C) +71.1
  D) +111.0
  Show Answer
  The correct answer is A .
• Question 2219: What volume of carbon (ll) oxide is produced by reacting excess carbon with 10 dm³ of oxygen? Options:
  A) 5 dm ³
  B) 20 dm ³
  C) 15 dm ³
  D) 10 dm ³
  Show Answer
  The correct answer is B .
• Question 2220:
  

  Use the section of the periodic table above to answer this question.

  Which of the indicate an alkali metal and a noble gas respectively?

  Options:
  A) M and E
  B) G and E
  C) R and L
  D) G and L
  Show Answer
  The correct answer is D .