Problem 161 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following \begin{tabular}{ll} \hline Column-I & Column-II \\ \hline (a) Magnesia & (p) \(\mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}\) \\ (b) Epsom salt & (q) \(\mathrm{MgO}\) \\ (c) Anhydrone & (r) \(\mathrm{CaH}_{2}\) \\ (d) Hydrolith & (s) \(\mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2}\) \\ \hline \end{tabular}

Step-by-Step Solution

Answer

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

Step 1: Identify the Column-I Terms

The terms in Column-I are Magnesia, Epsom salt, Anhydrone, and Hydrolith. We need to find the appropriate chemical compound from Column-II that matches each term.

Step 2: Match Magnesia to its Chemical Compound

Magnesia is commonly known as magnesium oxide. Thus, we match Magnesia with \( \mathrm{MgO} \), which corresponds to (q) in Column-II.

Step 3: Match Epsom Salt to its Chemical Formula

Epsom salt is the common name for magnesium sulfate heptahydrate. Therefore, Epsom salt corresponds to \( \mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O} \), which matches (p) in Column-II.

Step 4: Identify the Chemical Compound for Anhydrone

Anhydrone is another name for magnesium perchlorate, particularly used as a desiccant. So, Anhydrone corresponds to \( \mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2} \), which is (s) in Column-II.

Step 5: Determine the Compound for Hydrolith

Hydrolith is the name given to calcium hydride, which is \( \mathrm{CaH}_{2} \). Therefore, Hydrolith matches (r) in Column-II.

Key Concepts

Magnesia

Magnesia, scientifically known as magnesium oxide, is a white, powdery chemical compound with the formula \( \mathrm{MgO} \). This compound is found naturally as the mineral periclase. Magnesia is commonly used in a variety of industries due to its *refractory* properties. This means it can withstand extremely high temperatures.

Here are some key uses of Magnesia:

• **Refractory Material:** Used in the lining of kilns and furnaces.
• **Antacid:** Helps to neutralize stomach acid in medical treatments.
• **Laxative:** Utilized for its mild laxative properties.

Magnesia's stability and high melting point make it invaluable in processes involving extreme heat. It's an essential component in building materials and important for health-related applications.

Epsom Salt

Epsom salt, or magnesium sulfate heptahydrate, has the formula \( \mathrm{MgSO}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O} \). It is a mineral compound recognized for its therapeutic benefits. In everyday language, it's often recommended for its soothing properties when dissolved in baths.

Epsom salt is used in several ways:

• **Bathtime Soak:** Often added to baths to relieve muscle pain and stress.
• **Gardening:** Provides magnesium to plants, promoting healthier growth.
• **Beauty Treatments:** Used in exfoliation and skincare due to its texture.

Apart from its use in relaxation, Epsom salt serves agricultural purposes by supplementing magnesium deficiency in soil.

Anhydrone

Anhydrone refers to magnesium perchlorate, which appears as a powerful drying agent with the chemical formula \( \mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2} \). It's mainly used in laboratories to absorb water from gases and solvents.

Key characteristics of Anhydrone include:

• **Desiccant Use:** Highly effective in removing moisture and keeping environments dry.
• **Heat-Producing Reaction:** Its reaction with water is exothermic, meaning it releases heat.

Because of its water-attracting capabilities, Anhydrone is essential in processes where maintaining dry conditions is crucial, such as in the preparation of certain dry chemical reactions or storage.

Hydrolith

Hydrolith, known as calcium hydride, is represented by the formula \( \mathrm{CaH}_{2} \). It is used primarily as a drying agent or desiccant.

Some key uses of Hydrolith include:

• **Hydrogen Generation:** Reacts with water to release hydrogen gas.
• **Reducing Agent:** In chemical reactions, it can donate electrons to reduce other substances.

Hydrolith's capacity to produce hydrogen gas on contact with water makes it valuable for generating hydrogen in situ. It's a handy substance in the field of chemistry, especially for hydrogenation processes.