(a) Write names and formulae of hydrocarbons containing a single and a double bond (one example for each). Give one characteristic chemical property of each.
(b) What is a detergent ? Name one detergent.
(c) Why have detergents replaced soap as a washing agent ?
(a) Write names and formulae of hydrocarbons containing a single and a double bond (one example for each). Give one characteristic chemical property of each.
(b) What is a detergent ? Name one detergent.
(c) Why have detergents replaced soap as a washing agent ?
a) Methane is a hydrocarbon which has a single bond. Its formula is CH4.
The characteristic chemical property of methane is the substitution reaction. It is a reaction in which one or more hydrogen atoms are replaced by some other atoms.
Chemical equation:
CH4+Cl2sunlight−−−−−→CH3Cl+HCl
Ethene is a hydrocarbon containing a double bond. Its formula is C2H4.
The characteristic chemical property of ethene is the addition reaction. It is a reaction in which an unsaturated compound (ethene) is combined with another substance to form a single product (saturated compound).
Chemical equation:
CH2=CH2+H2Ni catalyst−−−−−−→HeatCH3−CH3
(b) Detergent, a sodium salt of a long chain benzene sulphonic acid, is a cleansing agent. It has cleansing properties in water. A detergent has two parts, a large non-ionic hydrocarbon group and an ionic group such as sulphonate group SO3−Na+. Name of a detergent is sodium n-dodecyl benzene sulphonate.
(c) Detergents have replaced soap as a washing agent because they do not form insoluble calcium and magnesium salts (scum) in hard water. The solubility of detergents, even in hard water, is better than a soap. Detergents also froth well.
a) Methane is a hydrocarbon which has a single bond. Its formula is CH4.
The characteristic chemical property of methane is the substitution reaction. It is a reaction in which one or more hydrogen atoms are replaced by some other atoms.
Chemical equation:
CH4+Cl2sunlight−−−−−→CH3Cl+HCl
Ethene is a hydrocarbon containing a double bond. Its formula is C2H4.
The characteristic chemical property of ethene is the addition reaction. It is a reaction in which an unsaturated compound (ethene) is combined with another substance to form a single product (saturated compound).
Chemical equation:
CH2=CH2+H2Ni catalyst−−−−−−→HeatCH3−CH3
(b) Detergent, a sodium salt of a long chain benzene sulphonic acid, is a cleansing agent. It has cleansing properties in water. A detergent has two parts, a large non-ionic hydrocarbon group and an ionic group such as sulphonate group SO3−Na+. Name of a detergent is sodium n-dodecyl benzene sulphonate.
(c) Detergents have replaced soap as a washing agent because they do not form insoluble calcium and magnesium salts (scum) in hard water. The solubility of detergents, even in hard water, is better than a soap. Detergents also froth well.
