Question 1: Define neutralisation in terms of acid-base reactions.

Answer: Neutralisation is a chemical reaction in which an acid reacts with a base to produce water and a salt, typically involving the combination of hydrogen ions (H⁺) and hydroxide ions (OH⁻).

Question 2: Explain the mechanism of how an acid reacts with a base during neutralisation.

Answer: An acid donates hydrogen ions (H⁺) to the solution, while a base donates hydroxide ions (OH⁻). When they react, H⁺ and OH⁻ combine to form water (H₂O), and the remaining ions form a salt.

Question 1: Calculate the volume of 0.5 mol/L hydrochloric acid (HCl) needed to neutralise 25 mL of 0.5 mol/L sodium hydroxide (NaOH). Use the neutralisation reaction: HCl + NaOH → NaCl + H₂O.

Answer: Volume of HCl = 25 mL (since molarities and volumes are equal, they neutralise each other exactly).

Question 2: If 40 mL of a 0.25 mol/L sulfuric acid (H₂SO₄) reacts completely with sodium hydroxide, what is the volume of 0.5 mol/L NaOH required? (Reaction: H₂SO₄ + 2 NaOH → Na₂SO₄ + 2 H₂O).

Answer: 10 mL of NaOH.

Question 1: Describe the main safety precautions to follow during a neutralisation experiment in the laboratory.

Answer: Wear safety goggles and gloves, handle acids and bases with care, add acid to water slowly, and work in a well-ventilated area.

Question 2: List the variables you would control or measure in an experiment to determine the neutralisation point of an acid and a base.

Answer: Variables include the volume and concentration of acid and base, temperature, and the pH level to identify the neutralisation point.

Question 1: A student titrates 25 mL of hydrochloric acid (HCl) with 0.1 mol/L sodium hydroxide (NaOH). It takes 30 mL of NaOH to reach neutralisation. Calculate the concentration of the HCl solution.

Answer: 0.12 mol/L

Question 2: In an experiment, 50 mL of an unknown acid reacts with 50 mL of 0.2 mol/L sodium hydroxide, producing a neutral solution. What can you infer about the molarity of the unknown acid?

Answer: The molarity of the unknown acid is 0.2 mol/L because it reacted completely with the base in equal volumes.

Question 1: Describe how neutralisation principles are applied in the treatment of acidic soil in agriculture.

Answer: Neutralisation is used to correct soil pH by adding bases like lime (calcium carbonate), which reacts with excess acidity, producing water and neutral salts, thereby making the soil suitable for crops.

Question 2: Explain the importance of neutralisation reactions in the development of antacid medicines for indigestion.

Answer: Antacids are bases that neutralise excess stomach acid (hydrochloric acid), providing relief from indigestion. These medicines work by reacting with HCl to form water and salt, reducing the acidity and alleviating symptoms.