Question 1: Explain the general process of making a salt from an acid and an alkali.

Answer: The process involves a neutralisation reaction where an acid reacts with an alkali to produce a salt and water. The salt is then separated and purified.

Question 2: What is the role of a precipitate in salt formation?

Answer: A precipitate is an insoluble solid that forms during the reaction, often used to isolate and purify the salt.

Question 1: Describe two common methods used to make salts in the laboratory.

Answer: One method is titration, reacting an acid with an alkali to form a soluble salt. Another is precipitation, where an insoluble salt is formed by mixing solutions of two salts.

Question 2: Identify safety precautions that should be taken when preparing salts in the lab.

Answer: Wear safety goggles and gloves, handle acids and bases carefully, work in a well-ventilated area, and dispose of chemicals responsibly.

Question 1: Calculate the volume of 0.1 mol/dm³ hydrochloric acid required to react completely with 25 g of sodium hydroxide (NaOH). (Molar mass of NaOH = 40 g/mol)

Answer: V = 100 cm³

Question 2: If 50 cm³ of dilute sulphuric acid (0.2 mol/dm³) reacts with excess sodium carbonate, what mass of sodium sulphate (Na₂SO₄) is produced? (Molar mass of Na₂SO₄ = 142 g/mol)

Answer: Approximately 2.84 g

Question 1: Outline the key variables that must be controlled during the titration method of making soluble salts.

Answer: Concentration of reactants, volume measured, temperature, and precise mixing to ensure accurate neutralisation.

Question 2: List at least two safety precautions to observe when handling acids and alkalis during salt preparation.

Answer: Use personal protective equipment (goggles and gloves) and work in a well-ventilated area.

Question 1: A student reacts 50 cm³ of 0.5 mol/dm³ hydrochloric acid with excess sodium hydroxide. Calculate the mass of sodium chloride (NaCl) produced. (Molar mass of NaCl = 58.5 g/mol)

Answer: Approximately 1.73 g

Question 2: Explain why some salts are soluble in water while others are insoluble, providing examples.

Answer: Solubility depends on the lattice energy and hydration energy. For example, sodium chloride is soluble, whereas barium sulfate is insoluble because of its high lattice energy.

Question 1: Describe one industrial process for producing salts on a large scale and mention its significance.

Answer: The Solvay process produces sodium carbonate (soda ash) used in glass making, detergents, and manufacturing chemicals.

Question 2: Explain how making salts is important for agriculture and food preservation.

Answer: Salts like potassium nitrate are used as fertilisers, and salts such as sodium chloride are used in preserving food by preventing microbial growth.