Question

Which of the following when dissolved in water forms a solution which is non-conducting?
A. Chile saltpetre
B. Potash alum
C. Green vitriol
D. Ethyl alcohol

Answer 1

Conductivity (also known as specific conductance) is the measure of its ability of an electrolyte solution to conduct electricity. Its SI unit is Siemens per meter. Conductivity can be explained in terms of degree of dissociation of the electrolyte.

Complete step by step answer:
Ethanol and methanol dissociate similar to dissociation of water. The dissociation of water is, substances only conduct electricity if they are free to move under an electric field to carry charge. In the case of ethanol, electrical conductivity is zero, since it does not contain any of the electrolytes that are required for electricity to flow through in a liquid. For alcohol ${\text{ROHROH}}$. It can also be explained that the self-ionization constant for water is almost the same for ethanol. The dielectric constant for ethanol is less than water. The lower dielectric constant in alcohols will further prevent self-ionization relative to water. So, for methanol and ethanol the self-dissociation into ions will be weaker than in water making it electrically non conducting.

So, the correct answer is Option D.

Note: Resistance is the extent to which the given electrolytic solution can resist the flow of electric current. The conductance is the reciprocal of resistance.
The conductance of a solution containing one mole of an electrolyte is called the molar conductivity or it is a function of the ionic strength of a solution or the concentration of salt. It can also be defined as the conducting power of all the ions which are obtained by dissolving a mole of electrolyte in a solution. It is the property of an electrolyte solution that can be used in finding the efficiency of an electrolyte in the conduction of electricity.