Read the passage given below and answer the following questions: … - Vidyadip

Question

Read the passage given below and answer the following questions:
Amines are basic in nature. The basic strength of amines can be expressed by their dissociation constant, $K_b$ or $pK_b$.
$\text{RNH}_2+\text{H}_2\text{O}\rightleftharpoons\text{RNH}^+_3+\text{OH}^-$
$\text{k}_\text{b}=\frac{[\text{RNH}^+_3][\text{OH}^-]}{[\text{RNH}_2]}\text{and}\text{ pk}_\text{b}=-\log\text{k}_\text{b}$
Greater the $K_b$ value or smaller the $pK_b$ value, more is the basic strength of a mine. Aryl amines such as aniline are less basic than aliphatic amines due to the involvement of lone pair of electrons on N-atom with the resonance in benzene. In derivatives of aniline, the electron releasing groups increase the basic strength while electron withdrawing groups decrease the basic strength. The base weakening effect of electron withdrawing group and base strengthening effect of electron releasing group is more marked at p-position than at m-position. a-Substituted aniline is less basic than aniline due to ortho effect and is probable due to combination of electronic and steric effect.
The following questions are multiple choice questions. Choose the most appropriate answer:

Which of the following has lowest $pK_b$ value?

The strongest base among the following is:

$C_6H_5NH_2$
$p-NO_2 - C_6H_4NH_2$
$m-NO_2 - C_6H_4NH_2$
$C_6H_5CH_2NH_2$

Maximum $pK_b$ value of:

$(CH_3CH_2)_2NH$
$(CH_3)_2NH$

The order of basic strength among the following amines in benzene solution is:

Methylamine is more basic than $NH_3$.
Amines form hydrogen bonds.
Ethylamine has higher boiling point than propane.
Dimethylamine is less basic than methylamine.

$CH_3CH_2NH_2$ contains a basic $-NH_2$ group, but $CH_3CONH_2$ does not because:

Acetamide is amphoteric in character.
In ethylamine the electron pair on N-atom is delocalised by resonance.
In ethylamine there is no resonance while in acetamide the lone pair of electrons on N-atom is delocalised and is less available for protonation.
None of these.

✓

Answer

(c)

(d) $C_6H_5CH_2NH_2$

(a)

(d) Dimethylamine is less basic than methylamine.

Explanation:
Dimethylarnine is more basic than methyl amine.

(c) In ethylamine there is no resonance while in acetamide the lone pair of electrons on N-atom is delocalised and is less available for protonation.

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 "Case study (4 Marks)" from Amines→Amines — all question types→Chemistry STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Read the passage given below and answer the following questions:
Under the normal conditions, noble gases are monoatomic and have closed shell electronic configuration. Lighter noble gases have low boiling points due to weak dispersion forces between the atoms and the absence of other interatomic interactions. Xenon, one of the important noble gas, forms a series of compounds with fluorine with oxidation number $+2, +4$ and $+6.$ All xenon fluorides are strong oxidising agents. $XeF_4$ reacts violently with water to give $XeO_3.$ The geometry of xenon compounds can be deduced by considering the total number of electron pairs in their valence shell.
The following questions are multiple choice questions. Choose the most appropriate answer:

Among noble gases (from He to Xe) only xenon reacts with fluorine to form stable xenon fluorides because xenon.

Has the largest size.
Has the lowest ionisation enthalpy.
Has the highest heat ofvapourisation.
Is the most readily available noble gas.

The structure of $XeO_3$ is:

Square planar.
Pyramidal.
Linear.
T-shaped.

$XeF_6$ is expected to be.

Oxidising agent.
Reducing agent.
Unreactive.
Strongly basic.

In the preparation of compound of xenon, Bartlett had taken $\text{O}_2^+\text{PtF}_6^-$ as a base compound. This is because,

Both $O_2$ and $Xe$ have same size.
Both $Xe$ and $O_2$ have same electron gain enthalpy.
Both have almost same ionisation enthalpy.
Both $Xe$ and $O_2$ are gases.

The oxidation state of xenon in $XeO_3$ is:

$+4$
$+2$
$+8$
$+6$

Number of molecules which must collide simultaneously to give product is called molecularity. It is equal to sum of coefficients of reactants present in stoichiometric chemical equation.
For reaction, $m_1A + m_2B \rightarrow$ Product
Molecularity $= [m_1 + m_2]$
ln complex reaction each step has its own molecularity which is equal to the sum of coefficients of reactants present in a particular step. Molecularity is a theoretical property. Its value is any whole number. Number of concentration terms on which rate of reaction depends is called order of reaction or sum of powers of concentration terms present in the rate equation is called order of reaction.
If rate equation ofreaction is: Rate $=\text{k}\cdot\text{C}^{\text{m}_1}_\text{A}\cdot\text{C}^{\text{m}_2}_\text{B}$
Then order of reaction $= m_1 + m_2.$
ln simple reaction, order and molecularity are same.
ln complex reaction, order of slowest step is the order ofover all reaction. This step is known as rate determining step. Order is an experimental property. Its value may be zero, fractional or negative.
The following questions are multiple choice questions. Choose the most appropriate answer:

Higher order$(> 3)$ reactions are rare due to:

Shifting of equilibrium towards reactants due to elastic collisions.
Loss of active species on collision.
Low probability of simultaneous collision of all the reacting species.
Increase in entropy and activation energy as more molecules are involved.

The molecularity of the reaction:

$6\text{FeSO}_4+3\text{H}_2\text{SO}_4+\text{KClO}_3\rightarrow\text{KCl}+3\text{Fe}_2(\text{SO}_4)_3+3\text{H}_2\text{O}$ is:

$6$
$10$
$3$
$7$

Which of the following statements is false in the following?

Order of a reaction may be even zero.
Molecularity of a reaction is always a whole number.
Molecularity and order always have same values for a reaction.
Order of a reaction depends upon the mechanism of the reaction.

The rate of reaction, $A + 2B →$ products, is given by the following equation:

$-\frac{\text{d}[\text{A}]}{\text{dt}}=\text{k}[\text{A}][\text{B}]^2$

If $B$ is present in large excess, the order of the reaction is:

Zero
First
Second
Third

The rate of the reaction, $A + B + C →$ products, is given by $\text{r}=\frac{\text{d}[\text{A}]}{\text{dt}}=\text{k}[\text{A}]^\frac{1}{2}[\text{B}]^\frac{1}{3}[\text{C}]^\frac{1}{4}.$ The order of the reaction is:

$\frac{1}{3}$
$\frac{1}{4}$
$\frac{1}{2}$
$\frac{13}{12}$

Read the passage given below and answer the following questions:
At $298\ K$, the vapour pressure of pure benzene, $C_6, H_6$ is $0.256$ bar and the vapour pressure of pure toluene $C_6 H_5 CH_3$ is $0.0925$ bar. Two mixtures were prepared as follows:

$7.8g of C_6 H_6 + 9.2g$ of toluene
$3.9g of C_6 H_6 + 13.8g$ of toluene

The following questions are multiple choice questions. Choose the most appropriate answer:

The total vapour pressure (bar) of solution I is.

$0.128$
$0.174$
$0.198$
$0.258$

Which of the given solutions have higher vapour pressure?

$I$
$II$
Both have equal vapour pressure
Cannot be predicted

Mole fraction of benzene in vapour phase in solution I is.

$0.128$
$0.174$
$0.734$
$0.266$

Which of the following statements is/are correct?

Mole fraction of toluene in vapour phase is more in solution I.
Mole fraction of toluene in vapour phase is less in solution I.
Mole fraction of benzene in vapour phase is less in solution I.

Only II
Only I
I and III
II and III

Solution I is an example of a/an.

Ideal solution.
Non-ideal solution with positive deviation.
Non-ideal solution with negative deviation.
Can't be predicted.

Read the passage given below and answer the following questions:
Metal carbonyl is an example of coordination compounds in which carbon monoxide (CO) acts as ligand. These are also called homoleptic carbonyls. These compounds contain both $\sigma$ and $\pi$ character. Some carbonyls have metal-metal bonds. The reactivity of metal carbonyls is due to (i) the metal centre and (ii) the CO ligands. CO is capable of accepting an appreciable amount of electron density from the metal atom into their empty $\pi$ or $\pi-\text{orbital}.$ These types of ligands are called $\pi-\text{accepter}$ or $\pi-\text{acid}$ ligands. These interactions increases the $\Delta_0$ value.
The following questions are multiple choice questions. Choose the most appropriate answer:

What is the oxidation state of metal in $[Mn_2(CO)_{10}]?$

$+1$
$-1$
$+2$
$0$

Among the following metal carbonyls, the $C-O$ bond order is lowest in:

$[Mn(CO)_6]^+$
$[Fe(CO)_5]$
$[Cr(CO)_6]$
$[V(CO)_6]^-$

Which of the following can be reduced easily?

$V(CO)_6$
$Mo(CO)_6$
$[Co(CO)_4]^-$
$Fe(CO)_5$

The oxidation state of cobalt in $K[Co(CO)_4]$ is:

$+1$
$+3$
$-1$
$0$

Structure of decacarbonyl manganese is:

Trigonal bipyramidial
Octahedral
Tetrahedral
Square pyramidal

A reaction is said to be of the first order if the rate of the reaction depends upon one concentration term only. For a first order reaction of the type $A →$ Products, the rate of the reaction is given as: rate $= k[A]$. The differential rate law is given as: $\frac{\text{dA}}{\text{dt}}=-\text{k}[\text{A}].$ The integrated rate law is: In $\frac{[\text{A}]}{[\text{A}]_0}=-\text{kt},$ [A] is the concentration of reactant left at time t and $[A]_0$ is the initial concentration of the reactant, k is the rate constant.
The following questions are multiple choice questions. Choose the most appropriate answer:

The unit of rate constant for a first order reaction is:

$S^{-1}$
$mol L^{-1} s^{-1}$
$L mol^{-1} s^{-1}$
$L^2 mol^{-2} s^{-1}$

Half-life period of a first order reaction is $10min$. Starting with initial concentration $12M$, the rate after 20min is:

$0.693 \times 3M min^{-1}$
$0.0693 \times 4M min^{-1}$
$0.0693 \times M min^{-1}$
$0.0693 \times 3M min^{-1}$

$50\%$ of a first order reaction is complete in $23$ minutes. Calculate the ti me required to complete $90\%$ of the reaction.

$70.4$ minutes.
$76.4$ minutes.
$38.7$ minutes.
$35.2$ minutes.

For a first order reaction, $(A) → $ products, the concentration of A changes from $0.1M$ to $0.025M$ in $40$ minutes. The rate of reaction when the concentration of A is $0.01M$, is:

$3.47 \times 10^{-4} M/ min$
$3.47 \times 10^{-5} M/ min$
$1.73 \times 10^{-4} M/ min$
$1.73 \times 10^{-5} M/ min$

The half-life period ofa 1st order reaction is $60$ minutes. What percentage will be left over after $240$ minutes?

$6.25\%$
$4.25\%$
$5\%$
$6\%$

Read the passage given below and answer the following questions:
Werner, a Swiss chemist in $1892$ prepared and characterised a large number of coordination compounds and studied their physical and chemical behaviour. He proposed that, in coordination compounds, metals possess two types of valencies, viz. primary valencies, which are normally ionisable and secondary valencies which are non-ionisable. ln a series of compounds of cobalt (III) chloride with ammonia, it was found that some of the chloride ions could be precipitated as $AgCl$ on adding excess of $AgNO_3$ solution in cold, but some remained in solution. The number ofions furnished by a complex in a solution can be determined by precipitation reactions. The measurement of molar conductance of solutions of coordination compounds helps to estimate the number of ions furnished by the compound in solution.
In these questions (Q. No. i-iv), a statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.

Assertion and reason both are correct statements and reason is correct explanation for assertion.
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Assertion is correct statement but reason is wrong statement.
Assertion is wrong statement but reason is correct statement.

The following questions are multiple choice questions. Choose the most appropriate answer:

Assertion: The complex $[Co(NH_3)_3Cl_3]$ does not give precipitate with silver nitrate solution.

Reason: The given complex is non-ionisable.

Assertion: The complex $[Co(NH_3)_4Cl_2]Cl$ gives precipitate corresponding to 2 mol of AgCl with $AgNO_3$ solution.

Reason: It ionises as $[Co(NH_3)_4Cl_2]^+ + Cl^-.$

Assertion: $CoCl_3. 4NH_3$ gives 1 mol of AgCl on reacting with $AgNO_3$, its secondary valency is 6.

Reason: Secondary valency corresponds to coordination number.

Assertion: 1 mol of $[CrCl_2(H_2O)_4]Cl· 2H_2O$ will give 1 mol of AgCl on treating with $AgNO_3$.

Reason: $Cl^-$ ions satisfying secondary valanceis will not be precipitated.

Assertion: $CoCl_3. 3NH_3$ is not conducting while $CoCl_3. 5NH_3$ is conducting.

Reason: The complex of $CoCl_3. 3NH_3$ is $[CoCl_3(NH_3)_3]$ while that of $CoCl_3· 5NH_3$ is $[CoCl(NH_3)_5]Cl_3$.

Read the passage given below and answer the following questions:
The aryl halides are relatively less reactive towards nucleophilic substitution reactions as compared to alkyl halides. This low reactivity can be attributed to the following factors:

The $C - X$ bond in halobenzene has a partial double bond character due to involvement of halogen electrons in resonance with benzene ring.
The $C - X$ bond in aryl halides is less polar as compared to that in alkyl halides as $sp^2$ hyridised carbon is more electronegative than $sp^3$ hybridised carbon.

In these questions (Q. No. i-Iv), a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

Assertion and reason both are correct statements and reason is correct explanation for assertion.
Assertion and reason both are correct statements but reason is not correct explanation for assertion.
Assertion is correct statement but reason is wrong statement.
Assertion is wrong statement but reason is correct statement.

Assertion: Primary benzylic halides are more reactive than primary alkyl halides towards $S_N1$ reactions.

Reason: Reactivity depends upon the nature of the nucleophile and the solvent.

Assertion: is more reactive than towards nucleophilic substitution reactions.

Reason: Tertiary alkyl halides react predominantly by $S_N1$ mechanism.

Assertion: Chlorobenzene is more reactive than p-chloroanisole to nucleophilic substitution reactions.

Reason: Greater the stability of carbanion, greater is its ease of formation and hence, more reactive is the aryl halide.

Assertion: $4-$Nitrochlorobenzene undergoes nucleophilic substitution more readily than chlorobenzene.

Reason: Chlorobenzene undergoes nucleophilic substitution by elimination-addition mechanism while 4-nitrochlorobenzene undergoes nucleophilic substitution by addition-elimination mechanism.

Assertion: Chlorobenzene is less reactive than benzene towards the electrophilic substitution reaction.

Reason: Resonance destabilises the carbocation.

Read the passage given below and answer the following questions:
Aldehydes and ketones are reduced to primary and secondary alcohols respectively by $NaBH_4$ or $LiAlH_4$ as well as catalytic hydrogenation. The carbonyl group of aldehydes and ketones is reduced to

group on treatment with Zn-Hg and cone. HCl (Clemmensen reduction) or with hydrazine followed by NaOH or KOH in highly boiling solvent such as ethylene glycol (Wolff-Kishner reduction).Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with $HNO_3, KMnO_4, K_2Cr_2O_7$ etc. Even mild oxidising agents mainlyTollens' reagent and Fehling's solution also oxidise aldehydes. Ketones are generally oxidised under vigorous conditions i.e., strong oxidising agents and at elevated temperatures, to give mixture of carboxylic acids having lesser number of C-atoms than the parent ketone.
The following questions are multiple choice questions. Choose the most appropriate answer:

Which of the following cannot be made by reduction of ketone or aldehyde with $NaBH_4$ in methanol?

1-Butanol
2-Butanol
2-Methyl-1-propanol
2-Methyl-2-propanol

The carbonyl compound producing an optically active product by reaction with $LiAlH_4$ is:

Propanone
Butanone
3-pentanone
Benzophenone

A substance $C_4H_{10}O (X)$ yields on oxidation a compound $C_4H_8O$ which gives an oxime and a positive iodoform test. The substance X on treatment with cone. $H_2SO_4$ gives $C_4H_8$. The structure of the compound (X) is:

$CH_3CH_2CH_2CH_2OH$
$CH_3CH(OH)CH_2CH_3$
$(CH_3)_3COH$
$CH_3CH_2- O - CH_2CH_3$

In the oxidation of by acidified $K_2Cr_2O_7$, the products are:

$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3-\ ^\text{14}\text{C}-\text{OH}$ and $\text{CH}_3\text{CH}_2\text{COOH}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3(\text{CH}_2)_2\text{COOH}-\text{C}-\text{OH}$ and $ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{COOH}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{CH}_2\text{COOH}+\text{HCOOH}$
None of these.

The appropriate reagent for the following transformation is:

$\text{Na}_2\text{NH}_2,^-\text{OH}$
$\text{NaBH}_4$
$\frac{\text{H}_2}{\text{Ni}}$
$\text{AICl}_3$

Read the passage given below and answer the following questions:
The addition reaction of enol or enolate to the carbonyl functional group of aldehyde or ketone is known as aldol addition. The $\beta-$ hydroxyaldehyde or $\beta-$hydroxyketone so obtained undergo dehydration in second step to produce a conjugated enone. The first part of reaction is an addition reaction and the second part is an elimination reaction. Carbonyl compound having $\propto-$hydrogen undergoes aldol condensation reaction.

The following questions are multiple choice questions. Choose the most appropriate answer:

Condensation reaction is the reverse of which of the following reaction?

Lock and key hypothesis.
Oxidation.
Hydrolysis.
Glycogen formation.

Which of the following compounds would be the main product of an aldol condensation of acetaldehyde and acetone?

$CH_3CH = CHCHO$
$CH_3CH = CHCOCH_3$
$(CH_3)_2C = CHCHO$
$(CH_3)_2C = CHCOCH_3$

Which combination of carbonyl compounds gives phenyl vinyl ketone by an aldol condensation?

Acetophenone and Formaldehyde.
Acetophenone and acetaldehyde.
Benzaldehyde and acetaldehyde.
Benzaldehyde and acetone.

Which of the following will undergo aldol condensation?

$HCHO$
$CH_3CH_2OH$
$C_6H_5CHO$
$CH_3CH_2CHO$

Which of the following does not undergo aldol condensation?

$CH_3CHO$
$CH_3CH_2CHO$
$CH_3COCH_3$
$C_3H_2CHO$

In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.
Assertion: According to Freundlich, $\frac{\text{x}}{\text{m}}=\text{k}.\text{P}^\frac{1}{\text{n}}$
Reason: The isotherm shows variation of the amount of gas adsorbed by the adsorbent with temperature.