Updated By SaraNextGen

On March 11, 2024, 11:35 AM

Question 3.7:

Why does the conductivity of a solution decrease with dilution?

Answer:

The conductivity of a solution is the conductance of ions present in a unit volume of the solution. The number of ions (responsible for carrying current) decreases when the solution is diluted. As a result, the conductivity of a solution decreases with dilution.

Question 3.8:

Suggest a way to determine the  value of water.

Answer:

Applying Kohlrausch’s law of independent migration of ions, the  value of water can be determined as follows:

Hence, by knowing the  values of HCl, NaOH, and NaCl, the  value of water can be determined.

Question 3.9:

The molar conductivity of 0.025 mol L−1 methanoic acid is

46.1 S cm2 mol⁻¹.

Calculate its degree of dissociation and dissociation constant. Given λ ^°(H⁺)

= 349.6 S cm² mol⁻¹ and λ ^°(HCOO−) = 54.6 S cm² mol

Answer:

C = 0.025 mol L⁻¹

Now, degree of dissociation:

Thus, dissociation constant: