Waec Chemistry Past Questions For Year 2022
Question 11
If 60 g of M combines with 24 g of oxygen, what would the empirical formula of the oxide be?
- A. MO
- B. MO\(_{2}\)
- C. MO\(_{3}\)
- D. MO\(_{4}\)
Question 12
Which of the following statements about the standard hydrogen electrode is not correct?
- A. The hydrogen gas is at a pressure of 1 atmosphere
- B. A solution containing 1 mol dm-3 of H+ (aq) ions is used
- C. A platinum electrode is used
- D. The temperature is kept at 20 °C
Question 13
A white precipitate was formed when BaCl\(_{2(aq)}\) was added to an aqueous solution
of a salt X. The precipitate dissolved in dilute HCl with rapid effervescence. Salt X is likely to contain
- A. SO\(_{4}\) \(^{2-}\) ions
- B. SO\(_{3}\) \(^{2-}\) ions
- C. NO\(_{3}\)- ions
- D. SO\(_{3}\) \(^{2-}\)- ions
Question 14
Increasing the temperature generally
- A. decreases the solubility of a solid in a liquid but increases the solubility of a gas in a liquid.
- B. increases the solubility of a solid in a liquid but decreases the solubility of a gas in a liquid.
- C. increases the solubility of both a solid and a gas in a liquid
- D. decreases the solubility of both a solid and a gas in a liquid
Question 15
If 5.0 g of marble reacts with 25.0 cm3 hydrochloric acid, which of the following combinations has the fastest reaction rate?
- A. Marble chips and 2.0 mol dm\(^{-3}\) HCl\(_{(aq)}\)
- B. Marble chips and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)
- C. Powdered marble and 2.5 mol dm\(^{-3}\) HCl\(_{(aq)}\)
- D. Powdered marble and 2.0 mol dm\(^{-3}\) HCl\(_{(aq)}\)
