VARDAAN LEARNING INSTITUTE

1. X (organic liquid, fruity smell, formed when ethanol reacts with ethanoic acid) = Ethyl Ethanoate (Ester).

2. A (turns alkaline $KMnO_4$ colourless) = Ethanol. B (product) = Ethanoic Acid. C (gas with brisk effervescence with $NaHCO_3$) = CO$_2$.

3. M (gas that decolourises Bromine water) = Ethene ($C_2H_4$). Test for unsaturation.

4. X (soapy solution that doesn't foam in hard water) = Soap. Y (soapy solution that foams in hard water) = Detergent. Detergents have charged ends that don't precipitate with $Ca^{2+}$ / $Mg^{2+}$ ions.

5. Covalent compounds have weak intermolecular forces (Van der Waals). Less energy is needed to break them, hence low melting/boiling points.

6. Covalent compounds are non-electrolytes as they do not have free ions. They consist only of neutral molecules and hence do not conduct electricity.

7. Glacial Acetic Acid = Pure, undiluted Ethanoic Acid ($CH_3COOH$). It's called 'glacial' because at temperatures below 16.6°C, it freezes to form ice-like crystals.

8. LPG consists mainly of saturated hydrocarbons (Butane, Propane). Saturated hydrocarbons burn completely with a clean blue flame, producing no soot or smoke.

9. Methanol is used to denature ethanol (making it Denatured Alcohol). It makes ethanol unfit for drinking as methanol is highly toxic and can cause blindness or death.

10. Soap is a sodium or potassium salt of long-chain fatty acids (like sodium stearate). Its molecule has a hydrophilic (ionic) head and a hydrophobic (hydrocarbon) tail.

11. In hard water, soaps react with $Ca^{2+}$ and $Mg^{2+}$ ions to form insoluble salts (scum). This wastes soap and leaves stains.

12. Micelle Formation: When soap is added to oily dirt, the hydrophobic tails attach to the oil, and the hydrophilic heads face outwards into water, forming a spherical cluster called a micelle. The micelle traps the dirt and is washed away with water.