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:

$\ce{C_6H_5NH_2}$
$\ce{p-NO_2 - C_6H_4NH_2}$
$\ce{m-NO_2 - C_6H_4NH_2}$
$\ce{C_6H_5CH_2NH_2}$

Maximum $pK_b$ value of:

$\ce{(CH_3CH_2)_2NH}$
$\ce{(CH_3)_2NH}$

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.

$\ce{CH_3CH_2NH_2}$ contains a basic $-NH_2$ group, but $\ce{CH_3CONH_2}$ 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) $

$(d)\ \ce{C_6H_5CH_2NH_2}$

$(a)$

$(d)$ Dimethylamine is less basic than methylamine.

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.

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Read the passage given below and answer the following questions: Glucose is known as dextrose because it occurs in nature as the optically active dextrorotatory isomer. lt is essential constituent of human blood. The blood normally contains $65$ to $110mg$ of glucose per $100mL \ ($hence named Blood sugar$)$. The level may be much higher in diabetic persons. The urine of diabetic persons also contain considerable amount of glucose. ln combined form, it occurs in cane sugar and polysaccharides such as starch and cellulose. Glucose has an aldehyde group $(-\ce{CHO}),$ one primary alcoholic group $(-\ce{CH_2OH})$ and four secondary alcoholic groups $(-\ce{CHOH})$ in their structure. Due to the presence five hydroxyl groups $(-OH)$. glucose undergoes acetylation. Glucose also undergoes oxidation with mild oxidising agents like bromine water as well as with strong oxidising agents like nitric acid. Since glucose is readily oxidised, it acts as a strong reducing agent and reduces Tollen's reagent and Fehling solution. Glucose exists in two crystalline forms: $\alpha - D -$ glucose and $\beta - D - $ glucose. If either of the two forms is dissolved in water and allowed to stand, the specific rotation of the solution changes gradually, until a constant value is obtained. This change is called mutarotation. 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 : A diabetic person carries a packet of glucose with him always.

Reason : Glucose increases the blood sugar level almost instantaneously.

Assertion : On oxidation with nitric acid, glucose as well as gluconic acid both yield saccharic acid.

Reason : The pentaacetate of glucose does not react with hydroxylamine indicating the absence of free $-\text{CHO}$ group.

Assertion : Glucose reacts with acetyl chloride to form pentaacetyl glucose.

Reason : The formation of pentaacetyl derivative confirms the presence of five $-OH$ groups in glucose.

Assertion : A certain compound gives negative test with ninhydrin and positive test with Benedict's solution, the compound is an amino acid.

Reason : Glucose is a monosaccharide.

Assertion : The rapid interconversion of $\alpha - D - $ glucose and $\beta - D -$ glucose in solution is known as racemisation.

Reason : Hydrolysis reaction will take place when a mineral acid is treated with sugar.

Read the passage given below and answer the following questions: Proteins are high molecular mass complex biomolecules of amino acids. The important proteins required for our body are enzymes, hormones, antibodies, transport proteins, structural proteins, contractile proteins etc. Except for glycine, all $\alpha$-amino acids have chiral carbon atom and most of them have L-configuration. The amino acids exists as dipolar ion called zwitter ion, in which a proton goes from the carboxyl group to the amino group. A large number of $\alpha$-amino acids are joined by peptide bonds forming polypeptides. The peptides having very large molecular mass (more than 10,000) are called proteins. The structure of proteins is described as primary structure giving sequence of linking of amino acids; secondary structure giving manner in which polypeptide chains are arranged and folded; tertiary structure giving folding, coiling or bonding polypeptide chains producing three dimensional structures and quaternary structure giving arrangement of sub-units in an aggregate protein molecule. 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: Except glycine, all naturally occurring CL-amino acids are optically active.

Reason: All naturally occurring CL-amino acids, except glycine, has at least one asymmetric carbon.

Assertion: All amino acids are optically active.

Reason: Amino acids contain asymmetric carbon atoms.

Assertion: In $\alpha$-helix structure, intramolecular H-bonding takes place whereas in $\beta$-pleated structure, intermolecular H-bonding takes place.

Reason: An egg contains a soluble globular protein called albumin which is present in the white part.

Assertion: Secondary structure of protein refers to regular folding patterns of continuos portions of the polypeptide chain.

Reason: Out of 20 amino acids, only 12 amino acids can be synthesised by human body.

Assertion: The helical structure of protein is stabilised by intramolecular hydrogen bond between -NH and carbonyl oxygen.

Reason: Sanger's reagent is used for the identification of N-tenninal amino acid of peptide chain.

Read the passage given below and answer the following questions:
A mixture of two aromatic compounds $(A)$ and $(B)$ was separated by dissolving in chloroform followed by extraction with aqueous $\ce{KOH}$ solution. The organic layer containing compound $(A),$ when heated with alcoholic solution of $\ce{KOH}$ produce $\ce{C_7H_5N (C)}$ associated with unpleasant odour.
The following questions are multiple choice questions. Choose the most appropriate answer:

What is $A?$

$\ce{C_6H_5NH_2}$
$\ce{C_6H_5CH_3}$
$\ce{C_6H_5CH_3}$
None of these.

The reaction of $(A)$ with alcoholic solution of $\ce{KOH}$ to produce $(C)$ of unpleasant odour is called:

Sandmeyer reaction.
Carbylamine reaction.
Ullmann reaction.
Reimer$-$Tiemann reaction..

The alkaline aqueous layer $(B)$ when heated with chloroform and then acidified give a mixture of isomeric compounds of molecular formula $\ce{C_7H_6O_2. (B)}$ is:

$\ce{C_6H_5CHO}$
$\ce{C_6H_5COOH}$
$\ce{C_6H_5CH_3}$
$\ce{C_6H_5OH}$

In the chemical reaction,
$\ce{CH_3CH_2NH_2 + CHCl_3 + 3KOH \rightarrow (A)+ (B) + 3H_2O,}$

$\ce{C_2H_5NC}$ and $\ce{KCl}$
$\ce{C_2H_5CN}$ and $\ce{KCl}$
$\ce{CH_3CH_2CONH_2}$ and $\ce{KCl}$
$\ce{C_2H_5NC}$ and $\ce{K_2CO_3}$

Direct nitration of an aromatic compound $(A)$ is not feasible because:

The reaction cannot be stopped at the mononitration stage.
A mixture of $o, m$ and $p-$nitroaniline is always obtained.
Nitric acid oxidises most of the aromatic compound to give oxidation products along with only a small amount of nitrated products.
All of the above.

Read the passage given below and answer the following questions:
An organic compound $(A)$ having molecular formula $C_6H_6O$ gives a characteristic colour with aqueous $FeCl_3$ solution. $(A)$ on treatment with $CO_2$ and $\text{NaOH}$ at $400K$ under pressure gives $(B),$ which on acidification gives a compound $(C).$ The compound $(C)$ reacts with acetyl chloride to give $(D)$ which is a popular pain killer.
The following questions are multiple choice questions. Choose the most appropriate answer:

Compound $(A)$ is:

$2-$Hexanol.
Dimethyl ether.
Phenol.
$2-$Methyl pentanol.

Compound $(C)$ is:

Salicylic acid.
Salicyladehyde.
Benzoic acid.
Benzaldehyde.

Number of carbon atoms in compound $(D)$ is:

$7$
$6$
$8$
$9$

The conversion of compound $(A)$ to $(C)$ is known as:

Reimer$-$Tiemann reaction.
Kolbe's reaction.
Schimdt reaction.
Swarts reaction.

Compound $(A)$ on heating with compound $(C)$ in presence of $POCl_3$ gives a compound $(D)$ which is used:

In perfumery as a ftavouring agent
As an antipyretic
As an analgesic
As an intestinal antiseptic.

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 $A \rightarrow$ 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 $10$ min. Starting with initial concentration $12M,$ the rate after $20$ min 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$, (A) \rightarrow$ 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 $1^{st}$ 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 $\text{AgCl}$ on adding excess of $\ce{AgNO_3}$ 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 $[\ce{Co(NH_3)_3Cl_3]}$ does not give precipitate with silver nitrate solution.

Reason : The given complex is non-ionisable.

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

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

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

Reason : Secondary valency corresponds to coordination number.

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

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

Assertion : $\ce{CoCl_3. 3NH_3}$ is not conducting while $\ce{CoCl_3. 5NH_3}$ is conducting.

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

Read the passage given below and answer the following questions: Amines are produced when an alcoholic solution of ammonia and an alkyl or a benzyl halide is heated in a sealed tube at 373K. This reaction is called ammonolysis and usually gives a mixture of primary, secondary and tertiary amines along with some quarternary ammonium salts. This reaction is an example of nucleophilic substitution reaction in which ammonia acts as a nucleophile due to the presence of a lone pair of electrons on the nitrogen atom. However this method cannot be used for the preparation of aryl amines. One of the most convenient methods for the preparation of aryl amines is reduction of nitro compounds. Aryl amines can also be prepared by reduction of nitrites or Gabriel phthalimide synthesis. 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: Ammonolysis of alkyl halides only produces 2° amines.

Reason: Ammonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.

Assertion: Gabriel-phthalimide reaction can be used to prepare both aryl and alkyl primary amines.

Reason: Aryl halides are more reactive alkyl halides towards nucleophilic substitution reactions.

Assertion: Anunonolysis method cannot be used for the preparation of aryl amines.

Reason: Aryl halides are much less reactive than alkyl halides towards nucleophilic substitution reaction.

Assertion: Ammonolysis can be used to prepare pure primary amines.

Reason: Ammonolysis of haloalkanes lead to multiple ammonium salts.

Assertion: Aromatic 1º amines can not be prepared by Gabriel phthalimide synthesis.

Reason: Aryl halides do not undergo nucleophilic substitution with anion formed by phthalimide.

Read the passage given below and answer the following questions:
Although chlorobenzene is inert to nucleophilic substitution, however it gives quantitative yield of phenol when heated with aq. $Na OH$ at high temperature and under high pressure. As far as electrophilic substitution in phenol is concemed the — $OH$ group is an activating group, hence, its presence enhances the electrophilic substitution at $o -$ and $p -$ positions.
The following questions are multiple choice questions. Choose the most appropriate answer:

Conversion of chlorobenzene into phenol involves:

Modified $S_N1$ mechanism.
Modified $S_N2$ mechanism.
Both $(a)$ and $(b).$
Elimination$-$addition mechanism.

Phenol undergoes electrophilic substitution more readily than benzene because:

The intermediate carbocation is a resonance hybrid of more resonating structures than that from benzene.
The intermediate is more stable as it has positive charge on oxygen, which can be better accommodated than on carbon.
In one of the canonical structures, every atom $($except hydrogen$)$ has complete octet.
The $— OH$ group is $o, p-$directing which like all other $o, p -$ directing group, is activating.

Phenol on treatment with excess of cone. $HNO_3$ gives:

$O -$ nitrophenol.
$P -$ nitrophenol.
$O -$ and $p -$ nitrophenol.
$2, 4, 6 -$ trinitrophenol.

Phenol is heated with a solution of mixture of $KBr$ and $KBrO_3.$ The major product obtained in the above reaction is:

$2 -$ bromophenol.
$3 -$ bromophenol.
$4 -$ bromophenol.
$2, 4, 6 -$ tribromophenol.

The major product of the following reaction is:

For the reaction : $2\text{NO}_\text{(g)}+\text{Cl}_{2\text{(g)}}\rightarrow2\text{NOCl}_\text{(g)},$ the following data were collected. All the measurements were taken at $263K.$

Experiment No.	Initial $\ce{[NO] (M)}$	Initial $\ce{[Cl_2] (M)}$	Initial rate of disapp. of $\ce{Cl_2 (M/ min)}$
$1.$	$0.15$	$0.15$	$0.60$
$2.$	$0.15$	$0.30$	$1.20$
$3.$	$0.30$	$0.15$	$2.40$
$4.$	$0.25$	$0.25$	$?$

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

The molecularity of the reaction is:

$1$
$2$
$3$
$4$

The expression for rate law is:

$\text{r}=\text{k}[\text{NO}][\text{Cl}_2]$
$\text{r}=\text{k}[\text{NO}]^2[\text{Cl}_2]$
$\text{r}=\text{k}[\text{NO}][\text{Cl}_2]^2$
$\text{r}=\text{k}[\text{NO}]^2[\text{Cl}_2]^2$

The overall order of the reaction is:

$2$
$0$
$1$
$3$

The value of rate constant is:

$150.32\ M^{-2}\ min^{-1}$
$200.08\ M^{-1}\ min^{-1}$
$177.77\ M^{-2}\ min^{-1}$
$155.75\ M^{-1}\ min^{-1}$

The initial rate of disappearance of $Cl_2$ in experiment $4$ is:

$1.75\ M\ min^{-1}$
$3.23\ M\ min^{-1}$
$2.25\ M\ min^{-1}$
$2.77\ M\ min^{-1}$

Read the passage given below and answer the following questions
Few colligative properties are:

Relative lowering of vapour pressure: depends only on molar concentration of solute $($mole fraction$)$ and independent of its nature.
Depression in freezing point: it is proportional to the molal concentration of solution.
Elevation of boiling point: it is proportional to the molal concentration of solute.
Osmotic pressure: it is proportional to the molar concentration of solute

A solution of glucose is prepared with $0.052 g$ at glucose in $80.2 g$ of water.$(KJ = 1.86K \ \text{kg \ mol}^{-1}$ and $K_b = 5.2K \ \text{kg \ mol}^{-1})$
The following questions are multiple choice questions. Choose the most appropriate answer:

Molality of the given solution is.

$0.0052m$
$0.0036m$
$0.0006m$
$1.29m$

Boiling point for the solution will be.

$373.05K$
$373.15K$
$373.02K$
$373.02K$

The depression in freezing point of solution will be.

$0.0187K$
$0.035K$
$0.082K$
$0.067K$

Mole fraction of glucose in the given solution is.

$6.28 \times 10^{-5}$
$6.28 \times 10^{-4}$
$0.00625$
$0.00028$

If same amount of sucrose $\ce{(C_{12} H_{22} O_{11})}$ is taken instead of glucose, then.

Elevation in boiling point will be higher.
Depression in freezing point will be higher.
Depression in freezing point will be lower.
Both $(a)$ and $(b).$