Question

Which of the following is not correct?
A. Equivalent conductivity $ - Scme{q^{ - 1}}$
B. Conductance $ - oh{m^{ - 1}}$
C. Specific conductance $ - Sc{m^{ - 1}}$
D. Cell constant $ - c{m^{ - 1}}$

Answer 1

Hint:In order to solve this question, we should know that we have given four physical quantities along with their standard SI units and here, we will discuss each option one by one and their SI units and then figure out which quantity is mentioned with their SI unit wrongly.

Complete step by step answer:
Considering first option (A) Equivalent conductivity $ - Scme{q^{ - 1}}$ , Equivalent conductivity is the specific conductance of any aqueous solution which contains $1$ equivalent weight of an electrolyte dissolved in the solution. The SI unit for equivalent conductivity is $Sc{m^2}e{q^{ - 1}}$ so, option (A) is incorrect.

Option (B) Conductance $ - oh{m^{ - 1}}$ since, conductance is the reciprocal of resistance and SI unit of conductance is $oh{m^{ - 1}}$ So, option (B) is correct.
Option (C) Specific conductance $ - Sc{m^{ - 1}}$ , specific conductance is the reciprocal of specific resistance and specific conductance has a SI unit of $Sc{m^{ - 1}}$ so, option (C) is also the correct one.

Option (D) Cell constant $ - c{m^{ - 1}}$ Cell constant is just the ratio of distance between the two electrodes and the area of the cross sectional of these electrodes, and Cell constant has a SI unit of $c{m^{ - 1}}$ . So, option (D) is also correct. So, the only physical quantity mentioned wrongly along with their SI units is Equivalent conductivity.

Hence, the correct option is B.

Note:It should be remembered that SI stands for International system of units which was formulated to normalize all the units which were used for measurements. Here, all the physical quantities mentioned in question are related to electrochemical cells.