IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :Types of chemical reaction-Acids/Base reactions
Topic :Types of chemical reaction-Weightage : 21 %
All Questions for Topic :acids and bases,neutral solutions,acid/base reactions,$\mathrm{pH}$ and indicators,formation of salts,uses of salts,redox reactions,reactivity series,extraction of metals and corrosion,electrochemical cells
Question : Types of Chemical Reaction – Acids and Bases [8 marks]
Question a [3 marks]
Explain what happens to the pH of water when iron oxide dissolves in it.
▶️ Answer/Explanation
• Iron oxide acts as a basic oxide
• Hydroxide ions (OH⁻) are released
• Neutralizes H⁺ ions in water
• Result: pH increases (solution becomes less acidic/more basic)
Question b [4 marks]
Describe two environmental impacts of changing water pH, including one effect on aquatic life.
▶️ Answer/Explanation
1. Impact on aquatic organisms:
• Most aquatic life survives only within narrow pH range (6.5-8.5)
• pH changes can kill sensitive species (e.g., fish eggs, amphibians)
2. Chemical solubility effects:
• Alters solubility of toxic metals (e.g., aluminum becomes more soluble at low pH)
• Affects nutrient availability for aquatic plants
Question c [1 mark]
Identify whether iron oxide is acidic or basic.
▶️ Answer/Explanation
Basic oxide
Question:
Write the balanced chemical equation for the reaction between calcium carbonate and hydrochloric acid. Can you predict the gas produced from the composition of the reactants?
▶️Answer/Explanation
Ans: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
The carbonate ion CO32– can be seen to contain the gas carbon dioxide CO2 within the formula.