16. (a) Which hydrocarbons burn with (i) non-sooty blue flame and (ii) sooty yellow flame? (b) What happens when methane reacts with chlorine? (c) What is rectified spirit? (d) Why does soap not work in hard water? (e) What is glacial acetic acid?
Answers
1. a)saturated hydrocarbon.
b) unsaturated hydrocarbon.
2. when methane reacts with chlorine it undergoes substitution reaction....
reactions are:
CH4 + Cl2-->CH3Cl + HCl
CH3Cl + Cl2-->CH2Cl2 + HCl
CH2Cl2 + Cl2-->CHCl3 + HCl
CHCl3 + Cl2-->CCl4 + HCl
3. a mixture of ethanol (95.6 per cent) and water produced as an azeotrope by distillation.
4. Hard water contains calcium and magnesium ions. When soaps are dissolved in hard water, these ions displace sodium or potassium from their salts and form insoluble calcium or magnesium salts of fatty acids. These insoluble salts separate as scum. This is the reason why soaps do not work in hard water.
5. Acetic acid that contains a very low amount of water (less than 1%) is called anhydrous (water-free) acetic acid or glacial acetic acid. The reason it's called glacial is because it solidifies into solid acetic acid crystals just cooler than room temperature at 16.7 °C, which ice.
A i because of incomplete combustion.
