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 1401: In the electrolysis of CuSo_4(g) using platinum electrode the reaction at the anode is Options:
  A) 4H+ 4e - 2H₂
  B) 4OH^-- 4e = 2H₂O + O₂
  C) 2OH - 2e_- = 2OH
  D) 2OH^- + 2OH = 2H₂O + O₂
  Show Answer
  The correct answer is B .
• Question 1402: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 2.0 mole of Q ³⁺
  B) 2.5 mole of R²⁺
  C) 4.0 mole of Y^-
  D) 3.0 mole of T^-
  Show Answer
  The correct answer is A .
• Question 1403:

  Which of the following are mixtures?

  i. Petroleum
  ii. Rubber latex
  iii. Vulcanizer's solution
  iv. Carbon (II) sulphide

  Options:
  A) i, ii and iii
  B) i, ii and iv
  C) i and ii only
  D) i and iv
  Show Answer
  The correct answer is A .
• Question 1404: Iron can be protected from corrosion by coating the surface with Options:
  A) gold
  B) silver
  C) copper
  D) zinc
  Show Answer
  The correct answer is D .
• Question 1405: A sample of orange juice is found to have a PH of 3.80. What is the concentration of the hydroxide ion in the juice? Options:
  A) 1.6 $\times$ 10^-4
  B) 6.3 $\times$ 10^-11
  C) 6.3 $\times$ 10^-4
  D) 1.6 $\times$ 10^-11
  Show Answer
  The correct answer is B .
• Question 1406:

  NaCI_(s) + H₂SO_4(I) → HCI_(g) + NaHSO_4(s).

  In the reaction above, H₂SO₄ behaves as?

  Options:
  A) a strong acid
  B) an oxidizing agent
  C) a good solvent
  D) a dehydrating agent
  Show Answer
  The correct answer is A .
• Question 1407:

  The solubility of the solids that dissolves in a given solvent with the liberation of heat will

  Options:
  A) increase with an increase in temperature
  B) decrease with an increase in temperature
  C) decrease with a decrease in temperature
  D) not be affected by changes in temperature
  Show Answer
  The correct answer is A .
• Question 1408:

  A solution X, on mixing with AgNO${}_3$ solution gives a white precipitate soluble in aqueous NH${}_3$, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

  Options:
  A) Al${}^{3+}$, Cl${}^{-}$
  B) Hg${}^{+}$, SO${}_4^{2-}$
  C) Pb${}^{2+}$, Cl${}^{-}$
  D) Ag${}^{+}$, SO${}_4^{2-}$
  Show Answer
  The correct answer is C .
• Question 1409:

  Which of these sources of water may likely contain the least concentration of Ca${}^{2+}$ and Mg${}^{2+}$?

  Options:
  A) Spring water
  B) River water
  C) Tap water
  D) Sea water
  Show Answer
  The correct answer is C .
• Question 1410:

  200cm³ each of 0.1M solutions of lead (II) trioxonitrate (V) and hydrochloric acid were mixed. Assuming that lead (II) chloride is completely insoluble, calculate the mass of lead (II) chloride that will be precipitated.

  [Pb = 207, Cl= 35.5, N = 14, O = 16]

  Options:
  A) 2.78g
  B) 5.56g
  C) 8.34g
  D) 11.12g
  Show Answer
  The correct answer is B .