Important Compounds NaOH Na2CO3 NaHCO3 NaCl - UNSOLVED PRACTICE SET
Chapter: s-Block Elements Alkali and Alkaline Earth Metals | Topic: Important Compounds NaOH Na2CO3 NaHCO3 NaCl
IMPORTANT COMPOUNDS NAOH NA2CO3 NAHCO3 NACL - UNSOLVED PRACTICE SET
Topic: Important Compounds NaOH Na2CO3 NaHCO3 NaCl
Multiple Choice Questions
Q1. Sodium hydroxide (NaOH) is manufactured industrially by:
- Solvay process
- Castner-Kellner process
- Contact process
- Haber's process
Q2. Sodium carbonate (Na₂CO₃) is commonly known as:
- Baking soda
- Washing soda
- Caustic soda
- Soda ash
Q3. Sodium bicarbonate (NaHCO₃) is used as an antacid because it:
- Is strongly alkaline
- Neutralises excess stomach acid
- Forms sodium carbonate in the stomach
- Is insoluble in water
Q4. In the Solvay process, the raw materials used are:
- NaCl, NH₃, CO₂, and limestone
- NaOH, HCl, and CO₂
- Na₂CO₃, Ca(OH)₂, and NH₃
- NaCl, H₂SO₄, and NH₃
Q5. When sodium bicarbonate is heated, it decomposes to give:
- Na₂CO₃ + H₂O
- Na₂CO₃ + CO₂ + H₂O
- NaOH + CO₂
- Na₂O + CO₂ + H₂O
Q6. Common salt (NaCl) is obtained from sea water mainly by:
- Filtration
- Evaporation and crystallisation
- Distillation
- Electrolysis
Short Answer Questions
Q7. Write the chemical equations for the Castner-Kellner process used for the manufacture of sodium hydroxide.
Q8. Explain why sodium carbonate (washing soda) is used for removing permanent hardness of water. Write the relevant chemical equation.
Q9. Your mother uses baking soda (NaHCO₃) while making cakes. What role does it play? Write the chemical reaction that occurs during baking.
Q10. Why is the Solvay process considered economical and environmentally friendly? Mention two advantages over the Leblanc process.
Q11. Sodium chloride is essential for our body, but excessive intake can be harmful. Name one health problem caused by excessive salt consumption and one disease caused by its deficiency.
Q12. How does sodium hydroxide react with aluminium metal? Write the balanced chemical equation and explain why aluminium containers are not used to store NaOH solution.
Long Answer Questions
Q13. Describe the Solvay process for the manufacture of sodium carbonate. Include:
(a) The raw materials required
(b) The chemical reactions involved in each step
(c) The role of ammonia in the process
(d) Why calcium chloride is obtained as a by-product
(e) Two advantages of this process
Q14. Discuss the preparation, properties, and uses of the following sodium compounds:
(a) Sodium hydroxide (caustic soda) — preparation by Castner-Kellner process
(b) Sodium bicarbonate (baking soda) — preparation, reaction with acids, and use as an antacid
Write balanced chemical equations for all reactions mentioned.
Q15. Sodium chloride is not just table salt — it has immense industrial importance. Discuss:
(a) How common salt is obtained from sea water in places like Gujarat and Tamil Nadu
(b) Its use in the manufacture of NaOH, Na₂CO₃, and chlorine
(c) Why iodised salt is recommended by the Indian government for public health
(d) The environmental impact of excessive salt mining and one sustainable practice
Numerical / Application-Based Problems
Q16. In the Solvay process, 106 kg of sodium carbonate (Na₂CO₃) is produced.
(a) Calculate the mass of sodium chloride (NaCl) required theoretically.
(b) Calculate the mass of ammonia (NH₃) that can be recovered and recycled.
(c) If the actual yield is 85% due to process losses, calculate the actual mass of NaCl consumed.
[Given: Atomic masses: Na = 23, C = 12, O = 16, Cl = 35.5, N = 14, H = 1]
Q17. A patient suffering from acidity is advised to take 0.84 g of sodium bicarbonate (NaHCO₃).
(a) Write the reaction of NaHCO₃ with stomach acid (HCl).
(b) Calculate the number of moles of NaHCO₃ in 0.84 g.
(c) Calculate the volume of CO₂ gas produced at STP when this amount reacts with excess HCl.
[Given: Atomic masses: Na = 23, H = 1, C = 12, O = 16; Molar volume at STP = 22.4 L]
Q18. A soap factory uses sodium hydroxide for saponification. In one batch, 200 kg of fat (tristearin, C₅₇H₁₁₀O₆) is treated with NaOH.
(a) Write the saponification reaction of tristearin with NaOH.
(b) Calculate the mass of NaOH required to completely saponify 200 kg of tristearin.
(c) If the cost of NaOH is ₹ 40 per kg, calculate the cost of NaOH for this batch.
[Given: Atomic masses: C = 12, H = 1, O = 16, Na = 23; Molar mass of tristearin = 890 g/mol]