Download App

2. Electrochemistry — Chemistry STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceChemistry2. Electrochemistry1 Mark
MCQ
Plotting $1 / \Lambda_{\mathrm{m}}$ against $\mathrm{c} \Lambda_{\mathrm{m}}$ for aqueous solutions of a monobasic weak acid ($HX$) resulted in a straight line with $y$-axis intercept of $\mathrm{P}$ and slope of $S$. The ratio $\mathrm{P} / \mathrm{S}$ is

$\left[\Lambda_{\mathrm{m}}=\right.$ molar conductivity

$\Lambda_{\mathrm{m}}^{\circ}=$ limiting molar conductivity

$\mathrm{c}=$ molar concentration

$\mathrm{K}_{\mathrm{a}}=$ dissociation constant of $\mathrm{HX}$ ]

  • ✓
    $\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}$
  • B
    $\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ} / 2$
  • C
    $2 \mathrm{~K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}$
  • D
    $1 /\left(\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}\right)$
✓

Answer

Correct option: A.
$\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}$
a
For weak acid, $\alpha=\frac{\Lambda_m}{\Lambda_0}$

$\mathrm{K}_\alpha=\frac{C \alpha^2}{1-\alpha} \Rightarrow \mathrm{K}_{\mathrm{s}}(1-\alpha)=C \alpha^2$

$\Rightarrow \mathrm{K}_\alpha\left(1-\frac{\Lambda_{\mathrm{m}}}{\Lambda_0}\right)=C\left(\frac{\Lambda_{\mathrm{m}}}{\Lambda_0}\right)^2$

$\Rightarrow \mathrm{K}_2-\frac{\Lambda_{\mathrm{m}} \mathrm{K}_{\mathrm{a}}}{\Lambda_0}=\frac{C \Lambda_{\mathrm{m}}^2}{\left(\Lambda_0\right)^2}$

Diride by ' $\Lambda_{\mathrm{m}}$ '

$\Rightarrow \frac{\mathrm{K}_{\mathrm{a}}}{\Lambda_{\mathrm{m}}}=\frac{\mathrm{C} \Lambda_{\mathrm{m}}}{\left(\Lambda_0\right)^2}+\frac{\mathrm{K}_{\mathrm{a}}}{\Lambda_0}$

$\Rightarrow \frac{1}{\Lambda_{\mathrm{m}}}=\frac{\mathrm{C} \Lambda_{\mathrm{m}}}{\mathrm{K}_{\mathrm{a}}\left(\Lambda_0\right)^2}+\frac{1}{\Lambda_0}$

Plot $\frac{1}{\Lambda_m}$ vi $C \Lambda_m$ has

Slope $=\frac{1}{\mathrm{~K}_{\mathrm{u}}\left(\Lambda_0\right)^2}=\mathrm{S}$

$\mathrm{y} \text {-intercept }=\frac{1}{\Lambda_0}=\mathrm{P}$

Then, $\frac{P}{S}=\frac{\frac{1}{\Lambda_0}}{\frac{1}{K_2\left(\Lambda_0\right)^2}}=\mathrm{K}_2 \Lambda_0$

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 "M.C.Q (1 Marks)" from 2. Electrochemistry→2. Electrochemistry — all question types→Chemistry STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

Which of following does not react with $HNO_2$ ?
→
Molecular formula ${C_6}{H_{12}}{O_6}$ is of
→
The rate of the reaction, $2NO + Cl_2 \rightarrow 2NOCl$ is given by the rate equation rate $= k[NO]^2[Cl_2].$ The value of the rate constant can be increased by
→
Coordination isomerism could be shown by
→
Reaction of primary amines with aldehyde yields:
→
The correct $\text{IUPAC}$ name of $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]$ is:
→
$2.33g$ of compound X(empirical formula $\mathrm{CoH}_{12} \mathrm{\sim N}_4 \mathrm{Cl}_3)$ upon treatment with excess $\ce{AgNO_3}$ solution produces $1.435g$ of a white precipitate. The primary and secondary valences of cobalt in compound $X,$ respectively, are. $[$Given $:$ Atomic mass$:\ \text{Co = 59, Cl = 35.5, Ag = 108].}$
→
Benzophenone does not react with
→
For the cell reaction $C{u^{2 + }}_{({C_1}aq)} + Zn(s) \Rightarrow Z{n^{2 + }}_{({C_2}aq)} + Cu(s)$ of an electrochemical cell, the change in free energy at a given temperature is a function of
→
Which of the following is general formula of alkane amide ?
→