CBSE 10th Acid Base Salt Important Question 2025 for Exam Day

CBSE 10th Acid Base Salt Important Question 2025 for Exam Day: The Central Board of Secondary Education (CBSE) has scheduled to conduct the CBSE Class 10 Science 2025 examination on February 20, 2025. The CBSE class 10 Science exam carries 100 marks. The theory exam is assigned for 80 marks and the rest of the 20 marks are allotted for the practical exams. In Chemistry, Chemical Substances- Nature and Behaviour unit will have a weightage of 25 marks out of which, 3 marks will be allotted for the Acid Base Salt section. Get the CBSE 10th Acid Base Salt Important Question 2025 for Exam Day available here.

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CBSE 10th Acid Base Salt Important Question 2025 for Exam Day

Students can check the CBSE Class 10th Acid Base Salt Important Questions 2025 below.

1. State the chemical name of Plaster of Paris. Write a chemical equation to show the reaction between Plaster of Paris and water.
   Answer: The chemical name of the plaster of Paris is calcium sulphate hemihydrate, and its chemical formula is CaSO₄ · 0.5H₂O. CaSO4. 1/2H2O + 3/2H2O = CaSO4. 2H2O is the chemical equation for the reaction of Plaster of Paris and water. Heat is released when the plaster of Paris reacts with water and crystallises.
   
   
2. The pH of a sample of vegetable soup was found to be 6.5. How is this soup likely to taste?
   Answer: A vegetable soup with a pH of 6.5 will likely taste slightly sour because it is weakly acidic.
3. How is tooth decay related to pH? How can it be prevented?
   Answer: Tooth decay is related to pH because the pH level in your mouth can drop below 5.5, which allows bacteria to grow and cause cavities. Brushing your teeth at least twice daily with fluoride toothpaste can prevent tooth decay.
   
   
4. Classify the following salts into acidic, basic, and neutral- Potassium Sulphate, Ammonium Chloride, Sodium Carbonate, Sodium Chloride
   Answer: Neutral Salts: Potassium sulphate sodium chloride, Basic Salts: Sodium carbonate, Acidic Salts: Ammonium chloride.
   
   
5. Dinesh is a farmer. He got the pH of his soil tested and followed the advice of Agricultural Scientists at Kissan Centre in growing crops. He got better quality of crops this year. Answer the following questions. 
   (i) Why should we get our soil tested?
   (ii) If the soil has a pH less than 7, how can we make it neutral?
   (iii) What values are possessed by Dinesh?
   Answer: (i) Plants need a specific pH test so that we can regularly check the pH range of the soil which is very important for its healthy growth.
   a. By knowing the pH range, we can determine the appropriate amount of fertilizers to use so that the production of crops may occur instantly.
   b. The soil pH is important because it affects the presence of nutrients in the soil.
   (ii) If the soil has a pH less than 7, we can make it neutral by using calcium carbonate (limestone) It increases the pH of the soil.
   (iii) Dinesh is concerned and aware.
   
   
6. A solution of Potassium Chloride when mixed with Silver Nitrate solution, an invaluable white substance is formed. Write the chemical reaction involved and also mention the type of chemical reaction.
   Answer: KCl aq + AgNO3 aq → AgCl s + KNO3 aqIt is a double displacement and precipitation reaction.
   
   
7. Crystals of a substance changed their colour on heating in a closed test tube but regained it after some time when they were allowed to cool down. Name the substance write its formula and explain the phenomenon involved.
   Answer: The crystals change their colours on heating in a closed tube but regain after some time because they hardly contain any contaminants in it. They can easily be affected by the heating. These crystals are generally formed from the aqueous solution and contain some water molecules in it. So the process by which the crystals change their colour on heating in a close test tube but regain its colour on cooling down is due to the phenomenon of water of crystallization. The phenomenon of water crystallization means that the substance contains a fixed number of the water molecules present in it in one formula unit of the salt. The other name for this process is water of hydration. As the water molecules hydrate the substance.
   The substance which undergoes this phenomenon is the hydrated copper sulphate. It has five water molecules. When we heat the blue crystal of hydrated copper sulphate the five water molecules get removed and the salt changes into white colour. But on cooling down it tends to regain its water of crystallization and its blue colour too.
   
   
8. A compound that is prepared from gypsum has the property of hardening when mixed with the proper quantity of water. Identify the compound and write its chemical.
   Answer: The compound is Plaster of Paris (POP). Its formula is CaSO4.2H2O, and its chemical name is calcium sulphate hemihydrate
   
   
9. When a magnesium ribbon burns in the air with a dazzling flame and forms white ash in magnesium oxide or is reduced, why?
   Answer: We can see that the Oxidation state of Mg changes from 0 in its free state to +2 in its oxide. Hence we can say that Mg has been oxidized. Similarly, the Oxidation state of O changes from 0 to -2, getting reduced in the process. Since both oxidation and reduction occur simultaneously, this is an example of a Redox reaction.
   
   
10. Name the reducing agent of the following reaction. 3MnO2 + 4AL = 3Mn + 2AL2O3.
    Answer: Aluminum is the reducing agent as it gets oxidized. Aluminum is more reactive than Manganese as Aluminum can displace Manganese from its compound.