1. 10 kg of CO2
2. 100 kg of CO2
3. 1000 kg of CO2
4. 10000 kg of CO2
Option “C” is correct The idea for carbon credits came from the Kyoto Protocol of 1997. This is placing a monetary value on the cost of polluting the air. A single carbon credit generally emits one metric ton(1,000 kg or 2,204 pounds) of carbon dioxide or the equivalent mass of another greenhouse gas.
42. Assertion (A): Detergent easily removes oil and dirt from dirty garments.
Reason (R) : Detergent increases the surface tension of water.
Code :1. Both (A) and (R) are true and (R) is the correct explanation of (A)
2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
3. (A) is true but (R) is false
4. (A) is false but (R) is true
Option “C” is correct Detergent easily removes oil and dirt from dirty garment as the surface tension of water is dramatically reduced by the addition of soap or detergent.
43. Percentage of Silver in German Silver is:
1. 1%
2. 5%
3. 0%
4. None of these
Option “C” is correct German Silver or Nickel silver is an alloy consisting 50% Copper, 35% Zinc and 15% Nickel. It doesn’t have silver.
44. Which one of the following is used in the manufacture of soaps?
Option “A” is correct Soap is a combination of animal fat or plant oil and caustic soda. Many vegetable fats including olive oil, palm kernel oil and coconut oil are also used in soap making.
45. Milk openly placed for sometime becomes sour due to-
Option “B” is correct Milk contains a sugar called lactose. It also contains harmless bacteria called lactobacillus, which uses glucose for energy and creates lactic acid as a by-product. It is the lactic acid which makes the milk sour. The presence of lactic acid or lactate in milk is due to the fermentation of lactose caused mainly by lactic bacteria.
46. Which one of the following substances is used in the preservation of food stuff?
Option “C” is correct The chemical formula of Sodium Benzoate is NaC7H5O2. It is widely used as food preservative.
47. ‘Humus’ is an example of-
1. Soil structure
2. Crystalloids
3. Organic colloids
4. None of the above
Option “C” is correct Humus usually refers to the natural decay of material such as leaves in the soil’s top layer. It is a dark organic material that forms in the soil when plant and animal matter decays.
48. Which of the following chemicals is used in foam fire extinguishers?
Option “A” is correct Aluminium sulphate is used in ‘foam’ fire extinguishers, which contains radium bicarbonate and aluminium sulphate in separate receptacles on being mixed they form the foam of bubbles of CO2.
Option “D” is correct Tartaric acid is the predominant organic acid in grapes.
50. In the case of rusting, the weight of iron-
1. Increases
2. Decreases
3. Remains the same
4. Uncertain
Option “A” is correct Due to rust, the weight of Iron increases as Iron is converted into-oxide after chemical reaction with Oxygen, in presence of humidity.
