4. Chemical Properties and Classifications

So if somebody comes and asks is the water contaminated, is water safe to drink? So your answer cannot be, your absolute final answer can be okay give me a month's time, I will analyze whether it contains all the one lakh chemicals that we know that are that exist in nature and then I will tell you in a month's time, that is not acceptable, people won’t wait for that long. So you need a quick answer. What is this quick answer, quick answer can never be a detailed answer, it has to be a short answer, but it gives you partial information, whether you. So we do whenever we do such things, we need a quick answer, we need what is called as Screening.

Screening is a preliminary analysis used to quickly determine if water is safe to drink. When someone inquires about the safety of water, an immediate response is crucial as thorough testing takes time. The screening process provides essential but incomplete information on water quality, serving as a first step in assessing contamination risk.

Imagine you're in a restaurant and see water served in a glass. You're hesitant to drink it because you can’t wait for weeks to test it in a lab. Instead, you do a quick examination: Is it clear? Does it have a foul smell? This quick evaluation is your screening process.

So drinking water, what will you look for in drinking water? When somebody gives you a glass of water, when will you not drink the glass of water? If it is coloured, if it is turbid, it means it is just not clear. Then smells or we call it as odor. Beyond these, these are visible parameters. You will quickly know that. Suppose it is none of this above, if you drink it, there could still be something in the water which does not give any of these, but these are very good preliminary screening factors.

When checking drinking water quality, there are key visible indicators. If the water is colored, turbid, or has an unpleasant odor, it is wise to avoid drinking it. Even if it appears clear and odorless, other contaminants may still be present, which highlights the importance of visible parameters in the initial screening of water quality.

Think of checking a fruit for freshness. If an apple has dark spots or looks bruised, you wouldn't eat it without thinking twice. Similarly, for water, if it's clear but smells bad, it's better to be cautious.

Dissolve is it is in the structure of the water and I think it does not form any precipitate, it is dissolved. clean, clear. Salt water for example, if you dissolve salt or sugar, it is dissolved. Turbid is not dissolved. The technical term that we use for this is Suspended Solids, something is suspended, means it just floats in the water. Odour is also dissolved because this you cannot see it, but you can smell it.

Water can contain two main types of components: dissolved solids and suspended solids. Dissolved solids are fully integrated into the water, such as when salt or sugar dissolves, creating a clear solution. In contrast, suspended solids remain partially intact and float in the water, contributing to turbidity. Additionally, dissolved odors indicate contaminants that may not be visible but can affect water quality.

Consider making a cup of hot chocolate. When you stir cocoa powder into hot water, it dissolves, making the water appear uniform. However, if you put in small chocolate chips, they may float on the surface – these represent suspended solids, while the dissolved cocoa is akin to dissolved solids.

So we are looking at a large number of chemicals which may be present in the water in the dissolved state. Inorganic mostly. Ions, things like ions they form, they form solution in water. So large number of inorganic salts, ions, they have very high solubility in water. You can also have organic compounds which are dissolved in water, but organic compounds by nature, organic compounds there is a classification of chemicals here, that that that makes it important.

Water can contain various chemicals, generally categorized into inorganic and organic compounds. Inorganic compounds, especially salts and ions, tend to have high solubility in water. Though some organic compounds can dissolve as well, they typically do so to a lesser extent due to their chemical structure. This distinction is essential for understanding water's chemical makeup and potential contamination.

Think of adding different ingredients to water. When you put in table salt (an inorganic compound), it dissolves easily. But when you try to mix in something like peanut butter (an organic compound), it doesn't dissolve as readily, illustrating the difference in solubility.

Total dissolved solids. Normally is this it is inorganic plus organic, you know. The definition the strict definition of total dissolved solids is everything, organic and organic everything together okay, but because inorganic dominates, we disregard the organic part whereever this is suitable. This TDS becomes a very simple measurement.

Total Dissolved Solids (TDS) refers to all dissolved substances in water, including both inorganic and organic materials. However, since inorganic materials dominate in most water samples, TDS often serves as a practical measurement of water quality, allowing for simpler assessment without heavily considering the organic compounds.

If you were measuring the sugar content in lemonade, you could just taste it for sweetness and not worry too much about the tiny bits of lemon pulp. Similarly, TDS focuses predominantly on dissolved inorganic substances while acknowledging the organic matter's presence without extensive analysis.

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