Problem 162 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following \begin{tabular}{ll} \hline List-I & List-II \\ \hline (a) Aqueous solution of (p) Anhydrone \(\mathrm{NaOCl}\) & (q) Javelle water \\ (b) \(\mathrm{KClO}_{3}\) & (r) Euchlorine \\ (c) \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2}\) & (s) Berthelot's salt \\ (d) \(\mathrm{Cl}_{2}\) and \(\mathrm{ClO}_{2}\) mixture & \end{tabular}

Step-by-Step Solution

Answer

(a - q), (b - s), (c - p), (d - r).

Step 1: Identify the compound in List-I

Start by identifying the common name or usage of each compound from List-I.- (a) Aqueous solution of \(\mathrm{NaOCl}\): Commonly known as bleach or Javelle water, used for cleaning and bleaching.- (b) \(\mathrm{KClO}_3\): Known for its use in fireworks or matches, sometimes referred to as Berthelot's salt.- (c) \(\mathrm{Mg}\left(\mathrm{ClO}_4\right)_2\): Recognized as an anhydrous compound which fits the use of anhydrone.- (d) \(\mathrm{Cl}_2\) and \(\mathrm{ClO}_2\) mixture: Known as a cholorinating agent and sometimes called Euchlorine.

Step 2: Match the compounds with List-II

Using the identifications from Step 1, match each item from List-I to List-II.- (a) Aqueous solution of \(\mathrm{NaOCl}\) matches with (q) Javelle water.- (b) \(\mathrm{KClO}_3\) is matched with (s) Berthelot's salt.- (c) \(\mathrm{Mg}\left(\mathrm{ClO}_4\right)_2\) aligns with (p) Anhydrone.- (d) \(\mathrm{Cl}_2\) and \(\mathrm{ClO}_2\) mixture corresponds to (r) Euchlorine.

Step 3: Verify the matches

Review each match to ensure it is correct based on chemical properties and historical naming.- (a) Javelle water is correct for \(\mathrm{NaOCl}\).- (b) Berthelot's salt correctly corresponds to \(\mathrm{KClO}_3\).- (c) Anhydrone is appropriately linked to \(\mathrm{Mg}\left(\mathrm{ClO}_4\right)_2\).- (d) Euchlorine matches the description of the \(\mathrm{Cl}_2\) and \(\mathrm{ClO}_2\) mixture.

Key Concepts

Bleach

Bleach is a household name for various cleaning and disinfecting solutions. A common type of bleach, known as Javelle water, is based on the compound sodium hypochlorite (\( \mathrm{NaOCl} \)). It's often used for whitening clothes, disinfecting surfaces, and cleaning.
Bleach works by breaking down into a substance called hypochlorous acid in water, which then deactivates various bacteria and viruses by disrupting their cellular processes.

• Always handle bleach with care – it can cause skin irritation.
• Never mix bleach with ammonia or acids, as it can produce dangerous gases.

Remember, bleach should be diluted with water to ensure safe use. This mixture can be applied to surfaces or fabrics depending on the cleaning task at hand.

Berthelot's salt

Berthelot's salt is a nickname given to the compound potassium chlorate, denoted as (\( \mathrm{KClO}_3 \)). This compound has interesting chemical properties and historical importance.
It was used in the past for creating fireworks and matches due to its ability to release oxygen rapidly when heated.

• Potassium chlorate can act as an oxidizing agent, meaning it can help other substances ignite more readily.
• It must be stored carefully to prevent accidental ignition.

While once widely used, safer alternatives have taken precedence due to its potentially explosive nature. Berthelot's salt showcases the fascinating balance of stability and reactivity in chemistry.

Anhydrone

Anhydrone refers specifically to (\( \mathrm{Mg(ClO}_4)_2 \)), which is magnesium perchlorate. It is known for being an excellent desiccant, meaning it is effective in removing moisture from the air or other substances.
In laboratories, anhydrone is used inside desiccators to keep an environment dry for water-sensitive chemical reactions.

• Its powerful moisture-absorbing capacity makes it useful in preserving food by preventing mold and decay.
• Always handle it with care to avoid unwanted chemical reactions.

Anhydrone’s value is largely in its ability to create dry conditions, rendering it critical for precise scientific experimentation and storage.

Euchlorine

Euchlorine is an older term that describes a dangerous mixture of chlorine gas (\( \mathrm{Cl}_2 \)) and chlorine dioxide (\( \mathrm{ClO}_2 \)). This yellowish-green gas was once used extensively as a bleaching and sterilizing agent.
Though not commonly used today due to safety concerns, understanding euchlorine helps us appreciate the historical methods of disinfection and bleach production.

• The mixture can be particularly corrosive and needs to be handled with extreme caution.
• This combination once held significance during times of early industrial practices for bleaching textiles.

By studying compounds like euchlorine, you can gain perspective on how chemical safety practices have evolved to where they are today.