4.2. Hydrophobicity and Organic Compounds

So, there is this term which is called as Hydrophobicity, we will come come back to this term later, the context of this is not with the in the in solubilities, it’s something else, so it is relative, okay, Anyway, so organic components also can be present, it’s finite solubility, but this is larger. For this one, solubility is very large, much much larger than that of organic compound, okay.

Hydrophobicity refers to the tendency of a compound to repel water. In simple terms, hydrophobic substances do not mix well with water. This is important because it affects how substances behave in water. Organic compounds are generally less soluble in water than inorganic compounds. For instance, oils and fats (which are organic compounds) do not dissolve in water because they are hydrophobic. The solubility refers to how well a substance can dissolve in another substance, and in this case, organic compounds have lower solubility in water compared to inorganic ones.

Think of oil and water in a salad dressing. When you mix oil (organic) with water (inorganic), the oil floats on top because it's hydrophobic. This is why, when you make a salad dressing, you often shake it up to temporarily mix them, but they will eventually separate again, highlighting the differences in their solubility.

So, there is one thing that you have to understand straightaway that many of these organic compounds also have solubility, all of them have solubilities, it’s it’s just low, it’s just water doesn’t like water, but it can be present in water, okay.

While organic compounds are primarily hydrophobic and have low solubility in water, it's crucial to understand that they still can dissolve to some extent. This means that even though water does not mix well with most organic compounds, small amounts can still be present in the water. This is often seen with substances like sugar or alcohol, which can dissolve in water despite being organic.

Imagine trying to mix sand (hydrophobic) in water. You might not be able to dissolve the sand completely, but if you add a little bit of salt (an inorganic compound), it dissolves easily. This illustrates how some organic compounds can be present in water, but generally not in large amounts.

If you look at the data of solubility versus the number of carbons, it is usually decreasing with the number of carbons as you, but if you have a group here, say I have a compound with an OH group or a COOH group or an NH or some such thing or even chlorine sometimes, some 2 of these have higher solubilities in water than something that does not have ‘H’, but still these compounds are not in comparison to inorganic salts, the solubility is very low.

The solubility of organic compounds often decreases as the length of their carbon chain increases. This means that larger organic molecules are generally less soluble in water. However, certain functional groups like -OH (hydroxyl) or -COOH (carboxyl) can increase solubility because they can interact more favorably with water. Despite this, even with these groups, organic compounds usually don't reach the high solubility that many inorganic salts do.

Think of glucose, a simple sugar which has several -OH groups. Glucose dissolves well in water, unlike long-chain fatty acids that may have many carbon atoms but lack such functional groups. It’s similar to how adding sugar to tea makes it sweet but isn’t comparable to adding salt, which dissolves completely and enhances the taste in a different way.

So what about suspended solids? What do you think are there in suspended solids? What is the classification what what type of material can be suspended in water, which means it is not dissolving, it’s an insoluble precipitate compound that doesn’t dissolve in water or it can be suspended.

Suspended solids refer to particles that are not dissolved in water and remain dispersed within it. These can include various materials such as dirt, silt, and other particulate matter. Unlike dissolved substances that become part of the water's liquid phase, suspended solids do not dissolve, and their presence can affect water quality by making it appear cloudy or turbid.

Imagine a glass of muddy water. The mud represents suspended solids, which gives the water its cloudy appearance. You can think of suspended solids like the crumbs that float on the surface of a settled bowl of soup – they are there but have not dissolved and will remain suspended unless filtered out.

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