set 2 MCQ Questions & Answers Detailed Explanation

Question : 1

Given below is an approximate composition of a substance :

• CaO - 60-70%,
• SiO₂ - 20-25%,
• Al₂O₃ - 5-10%,
• Fe₂O₃ - 2-3%

a) marble stone

b) cement

c) plaster of Paris

d) quartz

Question : 2

Consider the following statements

1. Soap cannot be used in acidic water.
2. Ionic part of a soap is —COO^– · Na⁺ .
3. Soap dissolves in water faster then detergent.

a) 3 only

b) 2 and 3

c) 1 and 2

d) 1 only

Question : 3

By which one among the following mechanisms, soap removes dirt (soil) from cloth?

a) Soap takes away the oily part of the soil and thus separates the soil from the cloth

b) Soap reacts with soil and converts them into soluble silicates

c) Soap dissolves the soil as such

d) The soap molecules bind with the soil, lift the soil and keep it suspended which can then be rinsed away