Download App

Electrochemistry — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryElectrochemistry3 Marks
Question
From the following molar conductivities at infinite dilution, calculate $\Lambda^0_{\text{m}}$ for $NH_4OH$.
$\Lambda^0_{\text{m}}\text{ for }\text{Ba(OH)}_2=457.6\Omega^{-1}\text{cm}^2\text{mol}^{-1}$
$\Lambda^0_{\text{m}}\text{ for }\text{BaCl}_2=240.\Omega^{-1}\text{cm}^2\text{mol}^{-1}$
$\Lambda^{0}_{\text{m}}\text{ for }\text{NH}_4\text{Cl}=129.8\Omega^{-1}\text{cm}^2\text{mol}^{-1}$
✓

Answer

$\Lambda^0_{\text{m}(\text{NH}_4\text{OH})}=\lambda^0_{\text{NH}^+_4}+\lambda^{0}_{\text{OH}^-}$
$=\Big(\lambda^0_{\text{NH}^+_4}+\lambda^0_{\text{Cl}^{-}}\Big)+\frac{1}{2}\Big(\lambda^0_{\text{Ba}^{2+}}+2\lambda^0_{\text{OH}^-}\Big)\\-\frac{1}{2}\Big(\lambda^0_{\text{Ba}^{2+}}+2\lambda^0_{\text{Cl}^-}\Big)$
$\Lambda^0_{\text{m}(\text{NH}_4\text{Cl})}+\frac{1}{2}\Big[\Lambda^0_{\text{m}(\text{BaOH})_2}\Big]-\frac{1}{2}\Big[\Lambda^0_{\text{m(BaCl}_2)}\Big]$
$129.8+\frac{1}{2}\times457.6-\frac{1}2{}\times240.6$
$=238.3\text{ ohm}^{-1}\text{cm}^2\text{mol}^{-1}$

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 "3 Marks Question" from Electrochemistry→Electrochemistry — all question types→Chemistry STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Vapour pressures of pure acetone and chloroform at $328$ K are $741.8$ mm Hg and $632.8$ mm Hg respectively. Assuming that they form ideal solution over the entire range of composition, plot $p_{total}, p_{chloroform},$ and $p_{acetone}$ as a function of $x_{acetone}$. The experimental data observed for different compositions of mixture is:
$100 \times x_{acetone}$ $0$ $11.8$ $23.4$ $36.0$ $50.8$ $58.2$ $64.5$ $72.1$
$p_{acetone}/ mm\ Hg$ $0$ $54.9$ $110.1$ $202.4$ $322.7$ $405.9$ $454.1$ $521.1$
$p_{chloroform}/ mm\ Hg$ $632.8$ $548.1$ $469.4$ $359.7$ $257.7$ $193.6$ $161.2$ $120.7$
Plot this data also on the same graph paper. Indicate whether it has positive deviation or negative deviation from the ideal solution.
→
An organic compound ' $A$ ' having molecular formula $\mathrm{C}_3 \mathrm{H}_6$ on treatment with aqueous $\mathrm{H}_2 \mathrm{SO} 4$ gives ' $B$ ' which on treatment with $\mathrm{HCl} / \mathrm{ZnCl}_2$ gives ' C '. The compound C on treatment with ethanolic KOH gives back the compound ' A '. Identify the compounds A, B, C.
→
How would you account for the following:
  1. Among lanthanoids, Ln (III) compounds are predominant. However, occasionally in solutions or in solid compounds, $+2$ and $+4$ ions are also obtained.
  2. The $E^o_{M^{2+}/M}$ for copper is positive $(0.34V)$. Copper is the only metal in the first series of transition elements showing this behaviour.
  3. The metallic radii of the third $(5d)$ series of transition metals are nearly the same as those of the corresponding members of the second series.
→
Carbonyl group is present in carboxylic acids and their derivatives, yet they do not show the properties of carboxylic group, why?
→
When a chromite ore (A) is fused with sodium carbonate in free excess of air and the product is dissolved in water, a yellow solution of compound (B) is obtained. After treatment of this yellow solution with sulphuric acid,compound (C) can be crystallised from the solution. When compound (C) is treated with KCl, orange crystals of compound (D) crystallise out. Identify A to D and also explain the reactions.
→
For the reaction:
$2A + B \rightarrow A_2B$
The rate$ = k[A][B]^2 $with $k = 2.0 \times 10^{–6} mol^{–2} L^2 s^{–1}$​​​​​​​. Calculate the initial rate of the reaction when $[A] = 0.1 mol L^{–1}, [B] = 0.2 mol L^{–1}​​​​​​​$. Calculate the rate of reaction after [A] is reduced to 0.06 mol $L^{–1}.$
→
$100\ g$ of liquid $A ($molar mass $140\ g\ mol^{–1})$ was dissolved in $1000\ g$ of liquid $B ($molar mass $180\ g\ mol^{–1}).$ The vapour pressure of pure liquid $B$ was found to be $500$ torr. Calculate the vapour pressure of pure liquid $A$ and its vapour pressure in the solution if the total vapour pressure of the solution is $475$ Torr.
→
Explain why the stability of oxoacids of chlorine increases in the order given below:
$HClO < HClO_2 < HClO_3 < HClO_4$
→
Give an example to show the effect of concentration of nitric acid on the formation of oxidation product.
→
Determine the amount of $CaCl_2 (i = 2.47)$ dissolved in $2.5$ litre of water such that its osmotic pressure is $0.75$ atm at $27^\circ C.$
→