Which one of the following may be termed as pure substance?

1

(a)

Sodium chloride

(b)

Soft drink

(c)

Aerosol

(d)

Soil

select a heterogeneous mixture of the following:

1

(a)

Air

(b)

NaCL in water

(c)

Emulsion

(d)

Alloy

Select a compound out of the following:

1

(a)

Air 

(b)

Solution

(c)

marble

(d)

Stainless steel

Which one of the following is a chemical change?

1

(a)

Evaporation of spirit

(b)

Freezing of water

(c)

Heating of copper and sulphur

(d)

Mixing of H₂ and O₂

A colloidal solution is:

1

(a)

homogeneous mixture

(b)

heterogeneous and transparent mixture

(c)

heterogeneous mixture in which particles can be seen with naked eyes

(d)

heterogeneous mixture in which particles cannot be seen with naked eyes

Components retain their properties in a................

1

(a)

mixture

A solution is a ...............mixture of two or more substances.

1

(a)

homogeneous

When no more solute can be dissolved in a solution at a given temperature, it is called a .................... solution

1

(a)

saturated

The particles of a .................. solution shows Tyndall effect.

1

(a)

colloidal

The solvent used to prepare colloidal solution shows Tyndall effect ___________

1

(a)

dispersing

What is chemically a pure substance?

2

(a)

How would you test the purity of a substance?

2

(a)

How will you prepare a saturated solution of copper sulphate in water at 50⁰ C? what will happen if this solution is allowed to cool?

2

(a)

What is the main difference between aqueous and non-aqueous solutions?

2

(a)

What are the two components of a solution? Write two properties of a solution.

2

(a)

How does the meaning of pure substance different for a common man that to a chemist? Explain.

5

(a)

How do you express concentration of a solution?

5

(a)

110 g of salt is present in 550 g of solution. Calculate the concentration of solution.

5

(a)

In what respect does a true solution differ from a colloidal solution and a suspension? How will you test whether a given solution is a colloidal solution or a suspension?

5

(a)

A silver ornament of mass m gram is polished with gold equivalent to 1% of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.

5

(a)