Important Salts — Set 4
Chemistry · महत्वपूर्ण लवण · Questions 31–40 of 40
Which salt is the main component of 'Rock Salt'?
Correct Answer: D. Sodium Chloride
Rock salt is the mineral form of sodium chloride, found in large underground deposits. It is often brown or yellow due to the presence of minor impurities. Unlike sea salt, it is mined directly from the earth.
What is the number of water molecules of crystallization in one formula unit of Copper Sulfate?
Correct Answer: D. 5
Copper Sulfate crystals contain exactly five molecules of water, giving it the formula $CuSO_4 \cdot 5H_2O$. This water is responsible for the blue color of the crystals. If the crystals are heated, they lose water and turn white.
Which salt is used as a raw material for making Sodium Hydroxide in the Chlor-alkali process?
Correct Answer: C. Sodium Chloride
Sodium Chloride solution, or brine, is electrolyzed to produce sodium hydroxide, chlorine, and hydrogen. This is one of the most important industrial processes for producing base chemicals. It relies on the abundance of common salt.
Which salt is formed when Sodium Hydroxide reacts with Sulfuric acid?
Correct Answer: C. Sodium Sulfate
Sodium Sulfate is produced through the neutralization reaction between this strong base and strong acid. Water is the other product formed during this exothermic chemical reaction. This salt is neutral in nature when dissolved in water.
Which of the following is a 'Basic Salt'?
Correct Answer: A. Sodium Acetate
Sodium Acetate is a basic salt because it is formed from a strong base and a weak acid. When dissolved in water, the acetate ions react to produce a slightly alkaline solution. It is commonly used in heating pads as a phase-change material.
What is the chemical name of the salt used to make 'Saltpeter'?
Correct Answer: D. Potassium Nitrate
Potassium Nitrate is the chemical name for the naturally occurring mineral saltpeter. It has historical importance in food preservation and as a component of explosives. Today, it is primarily used as a high-quality fertilizer for crops.
Which salt is used in the 'Fehling's solution' to test for reducing sugars?
Correct Answer: C. Copper Sulfate
Copper Sulfate is the active ingredient in Fehling's solution that reacts with sugars. In the presence of a reducing sugar, the blue solution forms a red precipitate. This is a standard qualitative test used in biochemistry laboratories.
Which salt is used as a 'Fire Retardant' in many building materials?
Correct Answer: A. Ammonium Phosphate
Ammonium Phosphate releases phosphoric acid when heated, which forms a protective char layer on surfaces. This layer prevents further combustion and slows down the spread of flames. It is a common additive in modern fire-resistant coatings.
Which salt is commonly known as 'Baking Powder' when mixed with a mild edible acid?
Correct Answer: D. Sodium Bicarbonate
Sodium Bicarbonate becomes baking powder when tartaric acid or a similar acid is added. The acid prevents the bitter taste of sodium carbonate that would otherwise be left behind. This mixture is preferred for baking over plain baking soda.
What is the color of the anhydrous form of Copper Sulfate salt?
Correct Answer: B. White
Anhydrous Copper Sulfate is white because it lacks the water molecules that produce its blue color. When water is added back to it, the salt turns blue again instantly. This change is often used as a chemical test for the presence of water.