Chemistry Past Questions And Answers
Which of the following gases is the most dangerous pollutant?
- A) Hydrogen sulphide
- B) Carbon (IV) oxide
- C) Sulphur (IV) oxide
- D) Carbon (II) oxide
Who proposed the planetary model of the atom with electrons orbiting the nucleus?
- A. Erwin Schr
- B. Ernest Rutherford
- C. Niels Bohr
- D. J.J. Thomson
(a) Define oxidation in terms of electron transfer.
(b) Consider the following: Cu\(_{(s)}\) + 2Ag\(^{+}_{(Ag)}\) \(\to\) Cu\(^{2+}_{(aq)}\) + 2Ag\(_{(s)}\)
(i) State the species that is reduced
(ii) Write half-cell equation for each of the species.
View Discussion (0)WAEC 1994 THEORYWhy is water often referred to as the universal solvent?
- A. Water is the most abundant substance on Earth
- B. Water is essential for all living organisms.
- C. Water is involved in many chemical reactions
- D. Water can dissolve a wide variety of substances due to its polar nature
The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (IV) solution is
- A) yellow to purple
- B) orange to green
- C) green to orange
- D) purple to yellow
Five metals represented by the letters V to Z are arranged in order of their reactivity as shown . V>W>X>Y>Z. Which of the metals is most likely extracted by the electrolysis of its fused chloride?
- A. V
- B. W
- C. X
- D. Z
The number of replaceable hydrogen atoms in one acid indicates its
- A. basicity
- B. acidity
- C. alkalinity
- D. reactivity
NO(g) + CO(g) ↔ (1)/(2)N2(g) + CO2(g) ∆H = -89.3 kj. What conditions would favour maximum conversion of nitrogen (II) oxide and carbon (II) oxide in the reaction above?
- A. Low temperature and high pressure
- B. High temperature and low pressure
- C. High temperature and high pressure
- D. Low temperature and low pressure
What is the value of x in the following equation? MnO- 4 + 4H+ + xe-→ MnO2+ 2H2O
- A. 2
- B. 3
- C. 4
- D. 7
Which of the following can be added to dissolve the precipitate formed in the reaction represented by the following equation? CaCl2(aq)+H2C2O4(s) ⇌ CaC2O2
- A. Calcium chloride solution
- B. Concentrated hydrochloric acid
- C. Ethanol
- D. Aqueous ammonia