Question

Which of the following is/are correct expression(s) regarding transport number?
Here,
$t_{+}\text{is the transport number of cation}$
$t_{-}\text{is the transport number of anion}$

• A. $t_{-}=\frac{\text{Total current carried by both the ions}}{\text{Current carried by the anions}}$
  
• B. $t_{-}=\frac{\text{Current carried by the anions}}{\text{Total current carried by both the ions}}$
• C. $t_{+}=\frac{\text{Total current carried by both the ions}}{\text{Current carried by the cations}}$
  
• D. $t_{+}=\frac{\text{Current carried by the cations}}{\text{Total current carried by both the ions}}$

Answer 1

Answer: (B), (D)

$t_{+}=\frac{\text{Current carried by the cations}}{\text{Total current carried by both the ions}}$

Transport number:
For electrolytic conductors, the current is carried by both cations and anions.Transport number of any ion is the fraction of total current (by all the ions) carried by that ion.
$t_{+}=\frac{\text{Current carried by the cations}}{\text{Total current carried by both the ions}}$

$t_{-}=\frac{\text{Current carried by the anions}}{\text{Total current carried by both the ions}}$

Adding both equations:
$t_{+}+t_{-}=1$