$ \text {Arrange the following alkenes in decreasing order of stability. } $
Choose the correct answer from the options given below:
III $>$ I $>$ II $>$ IV
III $>$ II $>$ I $>$ IV
I $>$ III $>$ II $>$ IV
$\mathrm{I}>\mathrm{III}>\mathrm{IV}>\mathrm{II}$
But-2-yne and hydrogen (one mole each) are separately treated with (i) $\mathrm{Pd} / \mathrm{C}$ and (ii) $\mathrm{Na} /$ liq. $\mathrm{NH}_3$ to give the products X and Y respectively.
Identify the incorrect statements.
A. X and Y are stereoisomers.
B. Dipole moment of $X$ is zero.
C. Boiling point of X is higher than Y .
D. X and Y react with $\mathrm{O}_3 / \mathrm{Zn}+\mathrm{H}_2 \mathrm{O}$ to give different products.
Choose the correct answer from the options given below :
B and D Only
A and C Only
A and B Only
B and C Only
$ \text { The final product }[\mathrm{B}] \text { is : } $
Consider the following reaction :
The product Y formed is :
2-methylhex-3-yne
5-methylhex-2-yne
Isopropylbut-1-yne
2-methylhex-2-yne
The dibromo compound $[\mathrm{P}]$ (molecular formula: $\mathrm{C}_9 \mathrm{H}_{10} \mathrm{Br}_2$ ) when heated with excess sodamide followed by treatment with dilute HCl gives [Q]. On warming [Q] with mercuric sulphate and dilute sulphuric acid yield $[R]$ which gives positive Iodoform test but negative Tollen's test. The compound $[\mathrm{P}]$ is :
Given below are two statements :
Statement I : Benzene is nitrated to give nitrobenzene, which on further treatment $
\text { with } \mathrm{CH}_3 \mathrm{COCl} / \mathrm{AlCl}_3 \text { will give }
$ 
Statement II : $-\mathrm{NO}_2$ group is a $m$-directing, and deactivating group.
In the light of the above statements, choose the most appropriate answer from the options given below
Statement I is incorrect but Statement II is correct
Both Statement I and Statement II are correct
Both Statement I and Statement II are incorrect
Statement I is correct but Statement II is incorrect
80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL . When the system is treated with KOH solution, the volume decreases to 64 mL . The formula of the hydrocarbon is :
$\mathrm{C}_2 \mathrm{H}_2$
$\mathrm{C}_2 \mathrm{H}_4$
$\mathrm{C}_4 \mathrm{H}_{10}$
$\mathrm{C}_2 \mathrm{H}_6$
Consider the following reaction of benzene.
In compound $(Q)$, the percentage of oxygen is $\_\_\_\_$ %. (Nearest integer)
Explanation:
Molecular mass of compound $Q$ is $157$.
In $Q$, oxygen contributes mass $16$ (for one oxygen atom).
So, percentage of oxygen in $Q$ is $\% \text{ of oxygen in product ' } Q \text{ ' is }=\frac{16}{157} \times 100=10.19 \%$
Nearest integer $=10$%.
The cycloalkene $(\mathrm{X})$ on bromination consumes one mole of bromine per mole of $(\mathrm{X})$ and gives the product $(\mathrm{Y})$ in which $\mathrm{C}: \mathrm{Br}$ ratio is 3:1. The percentage of bromine in the product $(\mathrm{Y})$ is $\_\_\_\_$ %. (Nearest integer)
(Given : molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{O}: 16, \mathrm{Br}: 80$ )
Explanation:
Bromination of a cycloalkene (one double bond) consumes 1 mole of $Br_2$ per mole of alkene, which means 2 bromine atoms add across the double bond.
So, product $(Y)$ is a dibromo compound.
Given in $(Y)$, the ratio $\mathrm{C}:\mathrm{Br} = 3:1$.
Let number of carbon atoms $= n$.
Number of bromine atoms $= 2$.
So,
$ \frac{n}{2} = \frac{3}{1} \;\Rightarrow\; n = 6 $
Hence $(Y)$ has formula:
$ \mathrm{C_6H_{10}Br_2} $
(since cyclohexene is $\mathrm{C_6H_{10}}$ and it adds $Br_2$)
Now molar mass of $(Y)$:
Carbon: $6 \times 12 = 72$
Hydrogen: $10 \times 1 = 10$
Bromine: $2 \times 80 = 160$
Total molar mass:
$ 72 + 10 + 160 = 242\ \mathrm{g\,mol^{-1}} $
Percentage of bromine:
$ \%Br = \frac{160}{242}\times 100 \approx 66.12\% $
Nearest integer $= \boxed{66\%}$.
Treatment of buta-1,3-diyne with NaNH2 (2 equivalents), followed by reaction with excess of trans-CH3-CH=CH-CH2-Br gives X as the major product. The maximum number of carbon atoms that are collinear (in a straight line) in X is _____.
Explanation:
The reactions which cannot be applied to prepare an alkene by elimination, are
Choose the correct answer from the options given below:
Given below are two statements:
Statement I : Ozonolysis followed by treatment with $\mathrm{Zn}, \mathrm{H}_2 \mathrm{O}$ of cis-2-butene gives ethanal.
Statement II : The product obtained by ozonolysis followed by treatment with $\mathrm{Zn}, \mathrm{H}_2 \mathrm{O}$ of 3, 6-dimethyloct-4-ene has no chiral carbon atom.
In the light of the above statements, choose the correct answer from the options given below
Predict the major product of the following reaction sequence:-
$ \text { Which compound would give 3-methyl-6-oxoheptanal upon ozonolysis? } $
Given below are two statements :
Statement (I) : Neopentane forms only one monosubstituted derivative.
Statement (II) : Melting point of neopentane is higher than n-pentane.
In the light of the above statements, choose the most appropriate answer from the options given below :
Match List - I with List - II.
| List - I (Reaction) |
List - II (Name of reaction) |
||
|---|---|---|---|
| (A) |  |
(I) | Lucas reaction |
| (B) | $ \mathrm{ArN}_2^{+} \mathrm{X}^{-} \xrightarrow[\mathrm{HCl}]{\mathrm{Cu}} \mathrm{ArCl}+\mathrm{N}_2 \uparrow+\mathrm{CuX} $ |
(II) | Finkelstein reaction |
| (C) | $ \mathrm{C}_2 \mathrm{H}_5 \mathrm{Br}+\mathrm{NaI} \xrightarrow[\text { Acetone }]{\text { Dry }} \mathrm{C}_2 \mathrm{H}_5 \mathrm{I}+\mathrm{NaBr} $ |
(III) | Fittig reaction |
| (D) | $ \mathrm{CH}_3 \mathrm{C}(\mathrm{OH})\left(\mathrm{CH}_3\right) \mathrm{CH}_3 \xrightarrow[\mathrm{ZnCl}_2]{\mathrm{HCl}} \mathrm{CH}_3 \mathrm{C}(\mathrm{Cl})\left(\mathrm{CH}_3\right) \mathrm{CH}_3 $ |
(IV) | Gatterman reaction |
$ \text { Choose the correct answer from the options given below : } $
Total number of sigma (σ) _______ and pi(π) ______ bonds respectively present in hex-1-en-4-yne are:
14 and 3
11 and 3
13 and 3
3 and 13
The product B formed in the following reaction sequence is:
Identify product [A], [B] and [C] in the following reaction sequence.
$\mathrm{CH}_3-\mathrm{C} \equiv \mathrm{CH} \xrightarrow[\mathrm{H}_2]{\mathrm{Pd} / \mathrm{C}}[\mathrm{A}] \xrightarrow[\text { (ii) } \mathrm{Zn}, \mathrm{H}_2 \mathrm{O}]{\text { (i) } \mathrm{O}_3}[\mathrm{~B}]+[\mathrm{C}]$
[A]: CH3—CH=CH2, [B]: CH3CHO, [C]: CH3CH2OH
[A]: CH3—CH=CH2, [B]: CH3CHO, [C]: HCHO
[A]: CH3CH2CH3, [B]: CH3CHO, [C]: HCHO
The product $(\mathrm{A})$ formed in the following reaction sequence is
Match List - I with List - II
| List - I (Isomers of $\mathrm{C}_{10} \mathrm{H}_{14}$ ) |
List - II (Ozonolysis product) |
||
|---|---|---|---|
| (A) |  |
(I) |  |
| (B) |  |
(II) |  |
| (C) |  |
(III) |  |
| (D) |  |
(IV) |  |
Choose the correct answer from the options given below :
Match the List - I with List - II
| List - I Name reaction |
List - II Product obtainable |
||
|---|---|---|---|
| (A) | Swarts reaction | (I) | Ethyl benzene |
| (B) | Sandmeyer's reaction | (II) | Ethyl iodide |
| (C) | Wurtz Fittig reaction | (III) | Cyanobenzene |
| (D) | Finkelstein reaction | (IV) | Ethyl fluoride |
Choose the correct answer from the options given below:
When sec-butylcyclohexane reacts with bromine in the presence of sunlight, the major product is :
The alkane from below having two secondary hydrogens is :
Given below are two statements :
Statement I : One mole of propyne reacts with excess of sodium to liberate half a mole of $\mathrm{H}_2$ gas.
Statement II : Four g of propyne reacts with $\mathrm{NaNH}_2$ to liberate $\mathrm{NH}_3$ gas which occupies 224 mL at STP.
In the light of the above statements, choose the most appropriate answer from the options given below :
Isomeric hydrocarbons → negative Baeyer’s test
(Molecular formula C9H12)
The total number of isomers from above with four different non-aliphatic substitution sites is -
Explanation:
Molecular formula of isomeric hydrocarbon $\to C_9H_{12}$ - Negative Baeyer's test
Baeyers test is given by compounds that contain readily active carbon-carbon double bond.
So, in a negative Baeyer's test, there is no readily active c = c.
Compounds that give negative Baeyer's test are alkanes and aromatic compounds.
C$_9$H$_{12}$ compound is not an alkane
(Alkane general formula C$_n$H$_{2n+2}$)
Hydrocarbons with the formula C$_9$H$_{12}$ are considered as aromatic and isomers of substituted benzene rings.
The possible isomers of C$_9$H$_{12}$ are
From these, total number of the isomers with four different non-aliphatic substitution sites are 2
 |
 |
 |
| Four positions (1,2,3,4) are different. So, it contain four different non-aliphatic substitution sites. | Four position (1,2,3,4) are different. So, it contain four different non-aliphatic substitution sites. | Four position (1,2,3,4) are not different. So, it contain four different non-aliphatic substitution sites. |
The sum of sigma (σ) and pi (π) bonds in Hex-1,3-dien-5-yne is ________.
Explanation:
The compound given is hex-1,3-dien-5-yne structure is
A doble bond has one $\pi$ bond and one sigma bond.
A triple bond has one sigma bond and two $\pi$ bonds.
For the one triple bond, number of $\pi$ bonds = 2
For one double bond, number of $\pi$ bond = 1
For two double bonds, number of $\pi$ bonds = 2
So, total number of $\pi$ bonds = 2 + 2 = 4
For sigma bonds, count all carbon - carbon bonds and carbon - hydrogen bonds except the $\pi$ bonds in double bonds and triple bond.
The total number of sigma bonds = 11
So, total number of bonds:
$\sigma=11$
$\pi=4$
Sum of $\sigma$ and $\pi$ bonds
$=11+4=15$
The compound with molecular formula $\mathrm{C}_6 \mathrm{H}_6$, which gives only one monobromo derivative and takes up four moles of hydrogen per mole for complete hydrogenation has _________ $\pi$ electrons.
Explanation:
Consider the depicted hydrogen (H) in the hydrocarbons given below. The most acidic hydrogen (H) is
B forms most stable conjugate base and hence $B$ is most acidic$
\text { Answer: Option (B) }
$
' $X$ ' is the isomer of $\mathrm{C}_6 \mathrm{H}_{14}$. It has four primary carbons and two tertiary carbons, ' $X$ ' can be prepared from which of the following reactions?
$ \begin{aligned} &\text { What are } X \text { and } Y \text { in the following reaction sequence? }\\ &\mathrm{C}_5 \mathrm{H}_{12} \mathrm{O} \xrightarrow[573 \mathrm{~K}]{\mathrm{Cu}} \mathrm{C}_5 \mathrm{H}_{10} \xrightarrow[\text { (ii) } \mathrm{Zn}+\mathrm{H}_2 \mathrm{O}]{\text { (i) } \mathrm{O}_3} X+Y \end{aligned} $
$ \text { Match the following } $
The correct answer is
A-II, B-IV, C-I, D-III
A-II, B-V, C-I, D-III
A-III, B-IV, C-II, D-I
A-II, B-III, C-IV, D-I
Chlorobenzene when subjected to fittig reaction gives a compound ' $X$ '. The sum of $\sigma$ and $\pi$ - bonds in $X$ is
30
28
18
29
Cumene on oxidation in air gives a compound, $X$. This on reaction with dilute acid gives $Y$ and $Z . Y$ reacts with sodium metal and not $Z$. What is $Z$ ?
Arrange the following in decreasing order of their boiling points
(A) 2-methylbutane
(B) 2, 2-dimethyl propane
(C) Pentane
(D) Hexane
$D>C>A>B$
B $>$ A $>$ C $>$ D
$D>A>C>B$
$B>C>A>D$
An alkyne has the molecular formula $\mathrm{C}_6 \mathrm{H}_{10}$. The number of 1 -alkyne isomers (excluding stereoisomers) possible for it is
2
5
3
4
Dehydration of an organic acid $X$ with concentrated $\mathrm{H}_2 \mathrm{SO}_4$ at 373 K gives $\mathrm{H}_2 \mathrm{O}$ and gas $Y$. The hybridisation of the carbon in $Y$ and nature of $Y$ are respectively.
$s p^2$, Neutral
$s p$, Neutral
$s p^2$, Acidic
$s p$, Acidic
Consider the given sequence of reactions,
$ \mathrm{C}_2 \mathrm{H}_6+\frac{3}{2} \mathrm{O}_2 \xrightarrow[\Delta]{(\mathrm{CH}, \mathrm{COO})_2 \mathrm{Mn}} X \xrightarrow{\mathrm{Na}} Y $
Electrolysis of aqueous solution of $Y$ gives gases $P$ and $Q$ at anode. $P$ and $Q$ are respectively
$\mathrm{C}_2 \mathrm{H}_6, \mathrm{CO}_2$
$\mathrm{CH}_4, \mathrm{CO}_2$
$\mathrm{C}_2 \mathrm{H}_6, \mathrm{H}_2$
$\mathrm{CH}_4, \mathrm{CO}$
Which of the following is an example of electrophilic substitution reaction?
$\mathrm{CH}_3 \mathrm{CHO}+\mathrm{HCN} \longrightarrow \mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CN}$
$\left(\mathrm{CH}_3\right)_3 \mathrm{CX}+\mathrm{H}_2 \mathrm{O} \longrightarrow\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{OH}+\mathrm{HX}$
$\mathrm{C}_6 \mathrm{H}_6+\mathrm{CH}_3 \mathrm{COCl} \xrightarrow{\mathrm{AlCl}_3} \mathrm{C}_6 \mathrm{H}_5\left(\mathrm{COCH}_3\right)+\mathrm{HCl}$
$\mathrm{BrCH}_2 \mathrm{CH}_2 \mathrm{Br}+\mathrm{Zn} \xrightarrow[\Delta]{\text { Alcohol }} \mathrm{CH}_2=\mathrm{CH}_2+\mathrm{ZnBr}_2$
An alkene $X$ on ozonolysis gives a mixture of simplest ketone $(Y)$ and 3-pentanone. The IUPAC name of the alkene $X$ is
2, 3-dimethylbut-2-ene
3-ethyl-4-methylpent-3-ene
3-ethyl-2-methylpent-2-ene
2-methyl-3-ethylpent-2-ene
Ethylene on reaction with cold, dilute alkaline $\mathrm{KMnO}_4$ at 273 K gives a compound ' $P$ '. This on polymerisation with which of the following gives dacron?
Consider the following sequence of reaction. In ' $Z$ ' the number of $s p^3$ carbons is ' $a$ ' and $s p^2$ carbons is ' $b$ '. Value of $(a+b)$ is
8
7
6
9
For the alkyne with formula $\mathrm{C}_6 \mathrm{H}_{10}$, the number of alkynes with acidic hydrogens is $x$ and number of alkynes with no acidic hydrogens is $y . x$ and $y$ are respectively
2,5
3,4
4,3
5,2
$ \left(\mathrm{CH}_3\right)_3 \mathrm{CH} \xrightarrow{\mathrm{KMnO}_4} X \xrightarrow[573 \mathrm{~K}]{\mathrm{Cu}} Y $
The number of $s p^3$ and $s p^2$ carbons in $Y$ are respectively
3,1
2,2
1,3
4,0
Consider the sets I, II and III. Identify the set(s) which is (are) correctly matched.
I. Staggered ethane > eclipsed ethane ..........torsional strain.
II. 2, 2-dimethylbutane > 2-methylpentane ......... boiling point
III. cis-but-2-ene > trans-but-2-ene ......... dipole moment
I, II only
II, III only
III only
I, II and III
The empirical formula weight of ' $Z$ ' in the given reaction sequence is
$ n \text {-propyl bromide } \xrightarrow[\text { Dry ether }]{\mathrm{Na}} X \xrightarrow[\substack{773 \mathrm{~K} \\ 20 \mathrm{~atm}}]{\mathrm{v}_2 \mathrm{O}_5} Y \xrightarrow[\text { UV } 500 \mathrm{~K}]{\mathrm{Cl}_2} Z $
47.5
54.5
84.5
48.5
So, the molecular formula is $\mathrm{C}_6 \mathrm{H}_6 \mathrm{Cl}$ and its empirical formula is CHCl . Thus, the empirical formula weight of $Z$ is 48.5Which one of the following compounds does not give benzoic acid when treated with alkaline $\mathrm{KMnO}_4$ ?
n-propyl benzene
Styrene
$t$-butyl benzene
Consider the following
Statement I Kolbe's electrolysis of sodium propionate gives $n$-hexane as product.
Statement II In Kolbe's process $\mathrm{CO}_2$ is liberated at anode and $\mathrm{H}_2$ is liberated at cathode.
Correct answer is
Both statement-I and statement-II are correct
Both statement-I and statement-II are not correct
Statement-I is correct, but statement-II is not correct
Statement-I is not correct, but statement-II is correct
The catalyst used for the isomerisation of $n$-alkanes to branched chain alkanes is
anhy. $\mathrm{AlCl}_3 / \mathrm{HCl}$
$\mathrm{Mo}_2 \mathrm{O}_3$
$\mathrm{FeCl}_3$
$\mathrm{TiCl}_4+\mathrm{R}_3 \mathrm{Al}$
What are $X$ and $Y$ respectively, in the following set of reactions?
