Question 1

Which of the following units is used to measure molar conductivity?

Accepted Answer

The correct option is S cm² mol⁻¹. Molar conductivity ($\Lambdam$) is defined as the conducting power of all the ions produced by dissolving one mole of an electrolyte in V cm³ of solution. Mathematically, $\Lambdam = \frac{\kappa 	imes 1000}{M}$, where $\kappa$ is conductivity and $M$ is molarity.

Question 2

What is the cell constant of a conductivity cell having distance between electrodes $l$ and cross-sectional area $A$?

Accepted Answer

The correct option is $l/A$. The cell constant ($G^$) is defined as the ratio of the distance between the electrodes ($l$) to the cross-sectional area of the electrodes ($A$). It is expressed as $G^ = l/A$. Its unit is cm⁻¹ or m⁻¹.

Question 3

According to Kohlrausch's law of independent migration of ions, the limiting molar conductivity of an electrolyte $\Lambdam^0$ is:

Accepted Answer

The correct option is the sum of the limiting molar conductivities of cations and anions. Kohlrausch's law states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte.

Question 4

Which of the following is a secondary battery?

Accepted Answer

The correct option is Lead storage battery. A secondary battery can be recharged by passing current through it in the opposite direction to that of its discharge so that it can be reused. Lead storage battery and nickel-cadmium storage cell are examples of secondary batteries, whereas dry cell and m

Question 5

The standard reduction potentials of three metals X, Y, and Z are -1.2 V, +0.5 V, and -3.0 V respectively. The reducing power of these metals will be in the order:

Accepted Answer

The correct option is Z > X > Y. Reducing power is inversely proportional to standard reduction potential ($E^0$). A more negative $E^0$ value means a stronger reducing agent. Given values: $E^0(Z) = -3.0$ V, $E^0(X) = -1.2$ V, $E^0(Y) = +0.5$ V. Therefore, the reducing power order is Z > X > Y.

Electrochemistry — NCERT Class 12 Chemistry Important Questions & Revision Notes