Chemistry Multiple Choice Questions on “Cleansing Agents”.
1. Which of the following causes soap to lather?
a) Sodium carbonate
b) Sodium rosinate
c) Sodium silicate
Clarification: Rosin is a chemical compound which is a gum that is added while making soaps. During saponification, it forms sodium rosinate which forms lathers.
2. When a soap is dissolved in ethanol followed by the evaporation of excess solvent, what type of soap is formed?
a) Transparent soap
b) Floating soap
c) Shaving soap
d) Laundry soap
Clarification: When the soap is dissolved in a solution of ethanol while making it and then evaporating the excess ethanol not used in the process, a transparent soap is formed.
3. What is the use of trisodium phosphate in soap powders?
a) To make the soap act rapidly
b) To make it lather
c) To prevent rapid drying
d) For good odour
Clarification: Sodium carbonate and trisodium phosphate acts a builders or building agents in powder soaps. These make the soap act more rapidly.
4. Dishwashing liquids are examples of ______
b) anionic detergents
c) cationic detergents
d) non-ionic detergents
Clarification: Dishwashing liquids are non-ionic detergents. They may be prepared from the reaction of polyethylene glycol with stearic acid. These do not contain any ionic entities in their whole chain.
5. Identify the cationic detergent from the following.
a) Cetyltrimethylammonium bromide
b) Sodium dodecyl sulphate
c) Pentaerythritol monostearate
d) Sodium lauryl sulphate
Clarification: Cetyltrimethylammonium bromide is a quaternary salt cation with bromine as the anion. The cationic part participates in the cleansing mechanism. Pentaerythritol monostearate is a non-ionic detergent, whereas sodium dodecyl sulphate and sodium lauryl sulphate are anionic detergents.