1.
What is cause of this environmental issue
Correct Answer
C. Both Nitrates and pHospahates
Explanation
Nitrates and phosphates are both known to contribute to environmental issues. Nitrates are commonly found in fertilizers and can contaminate water sources, leading to eutrophication and harmful algal blooms. Phosphates, also found in fertilizers and detergents, can have similar effects on water bodies, causing excessive growth of algae and depletion of oxygen. Therefore, the presence of both nitrates and phosphates can exacerbate environmental problems, making them the cause of this environmental issue.
2.
Depletion of [ ] kills aquatic organisms
Correct Answer
oxygen
Explanation
Depletion of oxygen kills aquatic organisms because they rely on oxygen dissolved in water for respiration. Without sufficient oxygen, they are unable to breathe properly and eventually suffocate. This can occur due to various factors such as pollution, excessive algae growth, or high water temperatures, which can reduce the amount of dissolved oxygen in the water. As a result, aquatic organisms, including fish and other marine life, cannot survive in oxygen-depleted environments.
3.
Alum causes clumping of mud particles
Correct Answer
A. True
Explanation
Alum is a compound that is commonly used in water treatment processes to clarify water by causing impurities to clump together. In the context of the given statement, alum is known to cause clumping of mud particles. When alum is added to muddy water, it reacts with the particles in the mud, causing them to bind together and form larger clumps. This process is called flocculation and is used to separate suspended solids from water. Therefore, the statement that alum causes clumping of mud particles is true.
4.
Which substance acts as a disinfectant in water purification?
Correct Answer
C. Chlorine
Explanation
Chlorine acts as a disinfectant in water purification because it has strong antimicrobial properties. When added to water, chlorine reacts with organic matter and kills bacteria, viruses, and other harmful microorganisms. It effectively destroys pathogens and prevents the spread of waterborne diseases, making it a commonly used disinfectant in water treatment processes.
5.
Which substance removes smell from water
Correct Answer
C. Activated charcoal
Explanation
Activated charcoal is a substance that is commonly used to remove odors and impurities from water. It has a highly porous structure, which allows it to effectively trap and absorb odor-causing molecules and contaminants. When water passes through activated charcoal, these molecules are adsorbed onto its surface, resulting in cleaner and odor-free water. Therefore, activated charcoal is the correct answer for removing smell from water.
6.
Desalination is another method to obtain pure water
Correct Answer
A. True
Explanation
Desalination is indeed another method to obtain pure water. It involves the process of removing salt and other impurities from seawater or brackish water, making it suitable for drinking and other purposes. This is typically done through techniques such as reverse osmosis or distillation. Desalination is particularly useful in areas where freshwater sources are scarce or contaminated, providing a reliable and sustainable source of clean water.
7.
Which non metal ion salts are added in water to prevent tooth decay?
Correct Answer
C. Fluoride
Explanation
Fluoride ions are added to water to prevent tooth decay. Fluoride helps to strengthen tooth enamel and makes it more resistant to acid attacks from bacteria in the mouth. It also helps to remineralize and repair early stages of tooth decay. Therefore, adding fluoride to water is an effective way to prevent tooth decay and promote good oral health.
8.
Hydrated copper sulfate is white solid
Correct Answer
B. False
Explanation
Hydrated copper sulfate is not a white solid. It is actually a blue solid. The blue color is due to the presence of water molecules in its crystal structure. When the water molecules are removed, the copper sulfate turns white.
9.
Rugs , plastics and wooden materials are separated by
Correct Answer
A. Screening
Explanation
Screening is a process used to separate different materials based on their size or shape. In this case, rugs, plastics, and wooden materials can be separated by using a screen with specific mesh size. The screen will allow smaller particles like rugs and plastics to pass through, while larger particles like wooden materials will be retained. Therefore, screening is the correct method for separating these materials.
10.
Sea water may boil at 98C
Correct Answer
B. False
Explanation
Sea water does not boil at 98°C. The boiling point of sea water is higher than that of pure water due to the presence of dissolved salts. On average, sea water boils at around 100.7°C. Therefore, the statement that sea water may boil at 98°C is false.