Download App

Electrochemistry — Chemistry STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceChemistryElectrochemistry3 Marks
Question
Explain the variation of molar conductivity with concentration for strong and weak electrolytes.
###
How is the molar conductivity of strong electrolytes at zero concentration determined by graphical method? Why is this method not useful for weak electrolytes?
✓

Answer

(i) As the dilution of an electrolytic solution increases, the dissociation of the electrolyte increases, hence the total number of ions increases, therefore, the molar conductivity increases.
Image
(ii) The increase in molar conductivity with increase in dilution or decrease in concentration is different for strong and weak electrolytes.
(iii) On dilution, the molar conductivity of strong electrolytes increases rapidly and approaches to a maximum limiting value at infinite dilution or zero concentration and represented as $\wedge \infty$ or $\wedge_0$ or $ \wedge^0{ }_m $. In case of weak. In case of weak electrolytes which dissociate less as compared to strong electrolytes, the molar conductivity is low and increases slowly in high concentration region, but increases rapidly at low concentration or high dilution. This is because the extent of dissociation increases with dilution rapidly.
(v) $\wedge_0$ values for strong electrolytes can be obtained by extrapolating the linear graph to zero concentration (or infinite dilution). However $\wedge_0$ for the weak electrolytes cannot be obtained by this method, since the graph increases exponentially at very high dilution and does not intersect $\wedge_{ m }$ axis at zero concentration.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Answer the following in brief." from Electrochemistry→Electrochemistry — all question types→Chemistry STD 12 Science question papers→Maharashtra Board STD 12 Science question papers→Maharashtra Board question paper generator→

Similar questions

Explain the sign convention used for $\Delta H$.
→
Classify the following polymers as straight-chain, branched-chain and cross-linked polymers.

Image

→
A chemical reaction occurs in the following steps:
(i) $NO _{2( g )}+ F _{2( g )} \longrightarrow NO _2 F _{( g )}+ F _{( g )} \quad$ (slow)
(ii) $F _{( g )}+ NO _{2( g )} \longrightarrow NO _2 F _{( g )}$ (fast)
(a) Write the equation of overall reaction.
(b) Write down rate law.
(c) Identify the reaction intermediate.
→
What is the action of the following on ethyl bromide:
(i) Alcoholic solution of potassium hydroxide
(ii) Moist silver oxide
(iii) Silver acetate?
→
In acidic solution, sucrose is converted to a mixture of glucose and fructose in pseudo first order reaction. It has been found that the con-centration of sucrose decreased from $20 mmol _{ L ^{-}}$ 1 to $8 mmol L ^{-1}$ in 38 minutes. What is the half-life of the reaction?
→
Conductivity of a solution is $6.23 \times 10^{-5} \Omega^{-1} cm ^{-1}$ and its resistance is $13710 \Omega$. If the electrodes are $0.7 cm$ apart, calculate the cross-sectional area of electrode.
→
Explain the structure of lactose.
→
How will you prevent the generation of waste or by-products?
→
Define the following terms :
(1) Standard electrode potential
(2) Standard oxidation potential
(3) Standard reduction potential.
→
Predict the signs of $\Delta H , \Delta S$ and $\Delta G$ of the system when a solid melts at 1 atmosphere and at (a) $-55^{\circ} C$ (b) $-95^{\circ} C$ (c) $-77^{\circ} C$, if the normal melting point of the solid is $-77^{\circ} C$.
→