Question
Explain the various uses of lanthanoids.
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Answer
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Derive the equation required for finding the activation energy.
A first order reaction takes 30 min for 50% completion, what would be time for its 90% completion.
Describe the common name system and IUPAC system of naming amines.
Draw the structures of optical isomers of :
(i) $\left[ Cr \left( C _2 O _4\right)_3\right]^{3-}$
(ii) $\left[ PtCl _2( en )_2\right]^{2+}$
(iii) $\left[ Cr \left( NH _3\right)_2 Cl _2( en )\right]^{+}$
→(i) $\left[ Cr \left( C _2 O _4\right)_3\right]^{3-}$
(ii) $\left[ PtCl _2( en )_2\right]^{2+}$
(iii) $\left[ Cr \left( NH _3\right)_2 Cl _2( en )\right]^{+}$
Match the items of Column $I$ and Column $II.$
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Column $I$
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Column $II$
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| $i.$ |
Lechlanche cell
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$a.$ |
Cell reaction $2H_2 + O_2 ⎯\rightarrow 2H_2O$
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| $ii.$ |
$Ni–Cd$ cell
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$b.$ |
Does not involve any ion in solution and is used in hearing aids.
|
| $iii.$ |
Fuel cell
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$c.$ |
Rechargeable.
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| $iv.$ |
Mercury cell
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$d.$ |
Reaction at anode, $Zn ⎯\rightarrow Zn^{2+} + 2e^-$
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$e.$ |
Converts energy of combustion into electrical energy.
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Answer the following questions:
→- The figure given alongside illustrates the first ionization enthalpies of first, second and third series of transition elements. Answer the question that follows:
- Which series amongst the first, second and third series of transition elements have the highest first ionization enthalpy and why?
- Separation of lanthanoid elements is difficult. Explain.
- $Sm^{2+}, Eu^{2+}$ and $Yb^{2+}$ ions in solutions are good reducing agents but an aqueous solution of $Ce^{4+}$ is a good oxidising agent. Why?
In a reaction between A and B, the inital rate of reaction (ro) was measured for different initial concentrations of A and B as given below :
What is the order of the reaction with respect to A and B?
→| $A / mol ^{-1}$ | 0.20 | 0.20 | 0.40 |
| $B / mol L ^{-1}$ | 0.30 | 0.10 | 0.05 |
| $r _0 / mol L ^{-1} s^{-1}$ | $5.07 \times 10^{-5}$ | $5.07 \times 10^{-5}$ | $1.43 \times 10^{-4}$ |
i. Give reasons :
a. Although $- \ce{NH2}$ group is o/p directing in electrophilic substitution reactions, yet aniline, on nitration gives good yield of $m-$nitroaniline.
b. $(\ce{CH 3)2NH}$ is more basic than $(\ce{CH3)3N}$ in an aqueous solution.
c. Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.
ii. Distinguish between the following:
a. $\ce{CH 3 CH 2 NH 2}$ and $(\ce{CH 3 CH 2)2NH}$
b. Aniline and $\ce{CH3NH2}$
→a. Although $- \ce{NH2}$ group is o/p directing in electrophilic substitution reactions, yet aniline, on nitration gives good yield of $m-$nitroaniline.
b. $(\ce{CH 3)2NH}$ is more basic than $(\ce{CH3)3N}$ in an aqueous solution.
c. Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.
ii. Distinguish between the following:
a. $\ce{CH 3 CH 2 NH 2}$ and $(\ce{CH 3 CH 2)2NH}$
b. Aniline and $\ce{CH3NH2}$
Write the $\text{IUPAC}$ names of the following coordination compounds:
$a.\ \left[ Pt \left( NH _3\right)_2 Cl \left( NO _2\right]\right.$
$b.\ K _3\left[ Cr \left( C _2 O _4\right)_3\right]$
$c.\ \left[ CoCl _2( en )_2\right] Cl$
$d.\ \left[ Co \left( NH _3\right)_5\left( CO _3\right)\right] Cl$
$e.\ Hg \left[ Co ( SCN )_4\right]$
→$a.\ \left[ Pt \left( NH _3\right)_2 Cl \left( NO _2\right]\right.$
$b.\ K _3\left[ Cr \left( C _2 O _4\right)_3\right]$
$c.\ \left[ CoCl _2( en )_2\right] Cl$
$d.\ \left[ Co \left( NH _3\right)_5\left( CO _3\right)\right] Cl$
$e.\ Hg \left[ Co ( SCN )_4\right]$
Write the applications of d- and f-block elements.