Nail polish remover contains

1. Introduction to Organic Compounds and Functional Groups (basic)

Welcome to our journey into the chemistry of everyday life! To understand why certain liquids can dissolve paint or why vinegar tastes sour, we must first meet the most versatile building block in nature: Carbon. Carbon is unique because it can form millions of compounds by bonding with itself and other elements—a feat that no other element achieves on such a massive scale Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.62. While the simplest organic compounds are hydrocarbons (made only of carbon and hydrogen), carbon is a very "friendly" element that frequently bonds with others like oxygen, nitrogen, and sulfur.

In a long chain of carbon atoms, one or more hydrogen atoms can be replaced by these other elements. When an element like oxygen or nitrogen steps in, we call it a heteroatom Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.66. These heteroatoms don't just sit there; they often form specific clusters known as Functional Groups. These groups are the "command centers" of a molecule—they dictate its chemical properties and how it will react, regardless of how long the carbon chain is.

Common functional groups include:

• Alcohol group (-OH): Found in sanitizers and beverages.
• Ketone group (>C=O): Found in 2-propanone (acetone), which is the primary solvent in nail polish removers.
• Carboxylic acid group (-COOH): Found in acetic acid (vinegar).

In chemistry, we use a systematic naming process to identify these groups. For instance, if a functional group is present, we modify the name of the base carbon chain (like propane) by adding a suffix or prefix Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.67. This helps scientists across the world immediately recognize the "personality" of the molecule just by reading its name.

Sources: Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.62; Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.66; Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.67

2. Principles of Solubility: 'Like Dissolves Like' (intermediate)

To understand why certain substances mix while others remain separate, we must look at the fundamental rule of chemistry: 'Like Dissolves Like'. At its heart, a solution is a uniform mixture where a solute (the substance being dissolved) is distributed evenly throughout a solvent (the dissolving medium) Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.135. Whether a solution forms depends on the chemical personality—specifically the polarity—of the molecules involved.

Molecules are generally classified as either polar or non-polar. Polar molecules, like H₂O, have an uneven distribution of electrical charge, creating "sticky" ends (positive and negative poles). Non-polar molecules, such as oils and fats, have a symmetrical charge distribution and lack these poles. The 'Like Dissolves Like' principle states that polar solvents will dissolve polar solutes, and non-polar solvents will dissolve non-polar solutes. This is why salt (polar/ionic) disappears into water, but an oil spill remains as a slick on the ocean surface.

Substance Type	Characteristics	Examples
Polar	Uneven charge; interacts with water.	Water, Sugar, Salt, Alcohol
Non-Polar	Even charge; does not mix with water.	Oil, Grease, Petrol, Wax

The solubility of a substance—the maximum amount of solute that can dissolve in a fixed quantity of solvent at a specific temperature—is a crucial measurement in both the lab and daily life Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.149. While temperature often increases the solubility of solids in liquids Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.137, no amount of heat will make a purely non-polar substance dissolve in a polar one if their chemical natures are fundamentally incompatible.

Sources: Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.135; Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.149; Science, Class VIII. NCERT (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.137

3. Hazardous Industrial Solvents: Benzene & Petroleum Derivatives (exam-level)

To understand hazardous industrial solvents, we must first look at hydrocarbons—compounds composed entirely of carbon and hydrogen. In chemistry, the rule 'like dissolves like' applies; therefore, these non-polar hydrocarbons are exceptionally good at dissolving other non-polar substances like oils, waxes, and greases NCERT Class X Science, Carbon and its Compounds, p.65. Among these, Benzene (C₆H₆) stands out as a primary industrial solvent. While it is a fundamental building block for plastics, resins, and synthetic fibers, it is highly regulated due to its carcinogenic (cancer-causing) properties. Chronic exposure to benzene and related hydrocarbons is linked to severe health issues, including lung and kidney damage Majid Hussain, Environment and Ecology, Environmental Degradation and Management, p.39. Apart from benzene, the petroleum industry produces various other derivatives through fractional distillation of crude oil Majid Husain, Geography of India, Energy Resources, p.15. These are often categorized as Volatile Organic Compounds (VOCs). Common industrial examples include:

• Petroleum Ether: Despite its name, it is not an ether but a mixture of aliphatic hydrocarbons (like pentane and hexane). It is used for extracting oils and in laboratory settings.
• Kerosene: Historically used for lighting and cooking, it is being phased out in India in favor of cleaner fuels like LPG Vivek Singh, Indian Economy, Subsidies, p.287. Industrially, it serves as a solvent in paints and pesticides.
• Toluene and Xylene: Often used as safer (though still hazardous) alternatives to benzene in paint thinners and adhesives.

These solvents are classified as hazardous because they evaporate easily at room temperature. When inhaled, these VOCs can cause immediate symptoms such as headaches, nausea, and loss of coordination, while long-term exposure may damage the liver and central nervous system Shankar IAS Academy, Environment, Environmental Pollution, p.66.

Solvent Type	Chemical Nature	Common Use	Primary Hazard
Benzene	Aromatic Hydrocarbon	Chemical synthesis	Carcinogenic; Bone marrow suppression
Petroleum Ether	Aliphatic Hydrocarbon mixture	Oil extraction	Highly flammable; Neurotoxicity
Kerosene	Complex Hydrocarbon blend	Fuel, Solvent in sprays	Respiratory distress if inhaled

Sources: NCERT Class X Science, Carbon and its Compounds, p.65; Environment and Ecology, Majid Hussain, Environmental Degradation and Management, p.39; Geography of India, Majid Husain, Energy Resources, p.15; Indian Economy, Vivek Singh, Subsidies, p.287; Environment, Shankar IAS Academy, Environmental Pollution, p.66

4. Common Organic Acids in Daily Life (basic)

In our daily lives, we encounter a variety of organic acids—compounds containing carbon that are naturally found in plants and animals. Unlike 'mineral acids' (such as Hydrochloric acid or Sulphuric acid) which are often highly corrosive and industrial, organic acids are generally weak acids. This means they do not fully ionize in water; they only release a small amount of hydrogen ions (H⁺), making many of them safe for us to eat and drink Science, Class X (NCERT 2025 ed.), Acids, Bases and Salts, p.26.

One of the most important organic acids is Ethanoic acid, better known as Acetic acid. When you find a 5-8% solution of this acid in water, it is called vinegar, a staple for preserving pickles. Pure acetic acid has a unique property: its melting point is 290 K, meaning it often freezes into solid crystals during winter. This characteristic led to its nickname, Glacial Acetic Acid Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.73.

Nature uses these acids in fascinating ways, from providing flavor to serving as defense mechanisms for insects. Here is a quick reference for common organic acids you will encounter:

Natural Source	Organic Acid Present
Vinegar	Acetic acid
Lemon / Orange	Citric acid
Tamarind	Tartaric acid
Tomato	Oxalic acid
Sour milk (Curd)	Lactic acid
Ant / Nettle sting	Methanoic acid (also called Formic acid)

Note: Science, Class X (NCERT 2025 ed.), Acids, Bases and Salts, p.28.

These acids also have functional roles in the kitchen. For instance, Baking Powder is a mixture of baking soda and a mild edible acid like Tartaric acid. When heated or mixed with water, the acid reacts with the soda to produce Carbon Dioxide (CO₂), which is what makes your cakes and bread rise to become soft and spongy Science, Class X (NCERT 2025 ed.), Acids, Bases and Salts, p.31.

Sources: Science, Class X (NCERT 2025 ed.), Acids, Bases and Salts, p.26, 28, 31; Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.73

5. Ketones: The Chemistry of Propanone (Acetone) (intermediate)

To understand ketones, we must first look at their defining feature: the carbonyl group (a carbon atom double-bonded to an oxygen atom, C=O). In a ketone, this carbonyl group is situated within the carbon chain, meaning the carbon in the C=O is bonded to two other carbon atoms. The simplest and most iconic member of this family is propanone, universally known as acetone.

According to chemical nomenclature, we name ketones by taking the parent alkane (propane, in this case), dropping the final '-e', and adding the suffix '-one' Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.67. Because the carbonyl group must be flanked by two carbons, propanone (CH₃COCH₃) is the smallest possible ketone; a "methanone" or "ethanone" cannot exist because they wouldn't have enough carbons to sandwich the carbonyl group.

Acetone is a polar aprotic solvent. This means it has a charge imbalance (polarity) that allows it to dissolve a wide range of substances, but it doesn't have the O-H bonds found in alcohols. This chemical profile makes it a "super-solvent." In everyday life, its most common application is as nail polish remover. It works by efficiently breaking the intermolecular forces in the tough, film-forming resins of the polish, turning the hardened lacquer back into a liquid state Science, Class VIII (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.135.

While it is highly effective, it is also very volatile (evaporates quickly) and flammable. In industrial settings, it is used in paint strippers and varnishes. It is far more potent than household reagents like acetic acid (vinegar), which lacks the specific solvency required to dissolve synthetic resins. Although "acetone-free" removers exist (often using ethyl acetate), propanone remains the gold standard for speed and efficiency in dissolving organic polymers.

Sources: Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.67; Science, Class X (NCERT 2025 ed.), Carbon and its Compounds, p.68; Science, Class VIII (Revised ed 2025), The Amazing World of Solutes, Solvents, and Solutions, p.135

6. Applied Chemistry: Chemicals in Personal Care Products (exam-level)

In the world of personal care, chemistry is the invisible hand that makes products functional. A classic example is nail polish remover. To understand how it works, we must first look at what it is trying to remove: nail polish is essentially a hardened film of polymers, resins, and pigments. To break this film down, we require a powerful organic solvent—a substance capable of dissolving another substance to form a solution.

The primary active ingredient in most commercial removers is Acetone (chemically known as 2-propanone or dimethyl ketone). Acetone is a colorless, highly flammable liquid with a distinctively sweet odor. From a chemical standpoint, it is a polar aprotic solvent. Its polarity allows it to interact with and break the bonds of the resins (like nitrocellulose) found in nail lacquer, effectively liquefying them so they can be wiped away. While acetic acid (ethanoic acid) is also a common organic compound found in households as vinegar Science, Class X, Carbon and its Compounds, p.73, it is a weak acid and lacks the specific solvency power required to dissolve hardened nail resins.

Solvent Type	Common Name / Use	Role in Personal Care
Acetone	2-propanone	Standard nail polish remover; highly efficient but can be drying to skin.
Ethyl Acetate	Acetone-free solvent	Found in "non-acetone" removers; gentler on skin and nails but works slower.
Benzene	Industrial solvent	Strictly avoided in cosmetics due to high toxicity and carcinogenic properties.

It is important for UPSC aspirants to distinguish between these functional chemicals. For instance, while we use silica gel in laboratory settings to keep air dry and prevent reactions Science, Class VII, The World of Metals and Non-metals, p.49, in personal care, we choose solvents based on their ability to interact with specific organic polymers without causing systemic harm to the human body. Even within the same chemical family, small changes in structure lead to vastly different applications—from the preservation of food using dilute acetic acid Science, Class X, Carbon and its Compounds, p.73 to the industrial cleaning power of ketones.

Sources: Science, Class X, Carbon and its Compounds, p.73; Science, Class VII, The World of Metals and Non-metals, p.49

7. Solving the Original PYQ (exam-level)

Now that you have mastered the basics of organic chemistry and functional groups, this question tests your ability to apply the principle of "like dissolves like." Nail polish is essentially a hardened film of polymers and resins. To remove it, we require a powerful organic solvent capable of breaking these molecular bonds. Acetone, also known as dimethyl ketone or 2-propanone, fits this role perfectly because its polar aprotic nature allows it to rapidly dissolve the resins and film-forming agents found in commercial lacquers, as detailed in PubChem.

In the UPSC context, you must often distinguish between industrial chemicals and household applications. When reasoning through the options, you can eliminate benzene immediately; while it is a solvent, it is a highly toxic carcinogen and would never be permitted in consumer cosmetics. Petroleum ether is a non-polar hydrocarbon used for industrial degreasing and is ineffective against the specific polar resins in polish. Finally, avoid the trap of acetic acid; though it is a common chemical (vinegar), it lacks the solvency power to liquefy hardened lacquer. Through this process of elimination, (A) acetone stands out as the only practical and scientifically sound choice.