Question

At a certain temperature and at infinit
dilution, the equivalent conductances of
sodium benzoate, hydrochloric acid and
sodium chloride are 240, 349 and 229 ohm
cm equiv respectively. The equivalent
conductance of benzoic acid in ohm cm
equiv' at the same conditions is​

Answer 1

In order to get benzoic acid u need C6H4COO- and H+

You will have to add sodium benzoate (Na+ C6H4COO-) and and hydrochloric acid(H+ and Cl-) and then subtract NaCl from it to get benzoic acid(C6H4COOH)

Equivalent conductance=(240+349)-229

=589-229

=360

I hope this helps,

Answer 2

Given:

Equivalent conductance (in ohm⁻¹ cm²/ equivalent) :-

Sodium Benzoate, λ(C₆H₅COONa) = 240

Hydrochloric Acid, λ(HCl) = 349

Sodium Chloride, λ(NaCl) = 229

To Find:

The equivalent  conductance of benzoic acid.

Calculation:

- The reaction is given as:

C₆H₅COONa + HCl → C₆H₅COOH + NaCl

- Applying Kohlrausch's law, we get

λ(C₆H₅COOH) =  λ(C₆H₅COONa) + λ(HCl) - λ(NaCl)

⇒ λ(C₆H₅COOH) = 240 + 349 - 229

⇒ λ(C₆H₅COOH) = 589 - 229

⇒ λ(C₆H₅COOH) = 360 ohm⁻¹ cm²/ equivalent.

- The equivalent  conductance of benzoic acid is 360 ohm⁻¹ cm²/ equivalent.