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 321: The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is Options:
  A) Na₂SO₄
  B) Na₂SO₃
  C) Na₂S
  D) Na₂CO₃
  Show Answer
  The correct answer is B .
• Question 322:

  3Cu_(s) + 8HNO_3(aq) 3Cu(NO₃)_2(aq) + 4H₂O_(l) + 2NO_(g)

  In the equation above, copper is

  Options:
  A) an electron acceptor
  B) a base
  C) an oxidizing agent
  D) a reducing agent
  Show Answer
  The correct answer is D .
• Question 323: Which of the following compounds is NOT the correct product formed when the parent metals is heated in air? Options:
  A) Calcium oxide (CaO)
  B) Sodium oxide (Na₂O)
  C) Copper (ll) oxide (CuO)
  D) Tri-iron tetroxide (Fe₃O₄)
  E) Aluminium oxide (Al₂O₃)
  Show Answer
  The correct answer is D .
• Question 324: Chlorine gas is prepared in the laboratory by Options:
  A) adding concentrated hydrochloric acid to solid manganese (IV) oxide
  B) aciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
  C) dropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
  D) aciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid
  Show Answer
  The correct answer is A .
• Question 325:

  When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

  Options:
  A) propylmethanoate
  B) ethylpropanoate
  C) methyl ethanoate
  D) methyl propanoate
  Show Answer
  The correct answer is B .
• Question 326: Which of the following relationships between the pressure P, the volume V and the temperature T, represents an ideal gas behaviour? Options:
  A) P $\alpha$ VT
  B) P $\alpha$ T/V
  C) PT $\alpha$ V
  D) PV $\alpha$ I/T
  E) P $\alpha$ V/T
  Show Answer
  The correct answer is B .
• Question 327:

  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 .
• Question 328: Given that electronegativity increases across a period and decreases down a group in the periodic table, in which of the following compounds will the molecules be held together by the strongest hydrogen bond? Options:
  A) HF_(g)
  B) NH_3(g)
  C) CH_4(g)
  D) HCl_(g)
  Show Answer
  The correct answer is A .
• Question 329: 2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is? Options:
  A) 200 g
  B) 160 g
  C) 100 g
  D) 50 g
  Show Answer
  The correct answer is C .
• Question 330: When a solid substance disappears completely as a gas on heating, the substance is said to have undergone Options:
  A) evaporation
  B) distillation
  C) crystallization
  D) sublimation
  Show Answer
  The correct answer is D .