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Biological Oxygen demand is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
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I believe the answer is C because the first two are mechanical hazards and C mentions plug which is electrical.
Based on the solubility observations, barium & aluminum could be distinguished by the addition of sodium chloride to the solutions.
<h3>What happens when NaCl is added to a solution?</h3>
- The ionic link that held sodium and chloride ions together is broken when water molecules force the ions apart.
- The sodium and chloride atoms are encircled by water molecules after the salt compounds are separated. After that, the salt dissolves and forms a homogenous solution.
- In order to keep patients from dehydrating, sodium chloride, an important nutrient, is employed in healthcare. It is employed as a spice to improve flavor and as a food preservative. Additionally, sodium chloride is employed in the production of polymers and other goods. Additionally, it is used to de-ice sidewalks and roadways.
- Adding water to sodium chloride results in a physical change because no new product is created.
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Atoms in covalent bonds do combine so as to be stable. As covalent bond consist non metals e.g O2 in this example each atom has vacance of 2 orbitals/ electrons so shairing electrons result their stability
