Hydrocarbons - Organic Chemistry - Chemistry Previous Year Questions

The alkane which is next to methane in homologous series can be prepared from which of the following reactions?

$ \text { I. } 2 \mathrm{CH}_{3} \mathrm{Br} \xrightarrow[\text { Dry ether }]{\mathrm{Na}} $

II. $\mathrm{CH}_{3} \mathrm{COOH} \xrightarrow[\mathrm{CaO}, \Delta]{\mathrm{NaOH}}$

III. $\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}_{2} \xrightarrow{\mathrm{H}_{2} / \mathrm{Pt}}$ IV. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br} \xrightarrow[\mathrm{H}^{+}]{\mathrm{Zn}}$

What is ' $ Y $ ' in the following set of reactions?

$$\mathrm{C}_3 \mathrm{H}_4 \xrightarrow[\substack{\mathrm{Hg}^{2+} / \mathrm{H}^{+} \\ 333 \mathrm{~K}}]{\mathrm{H}_2 \mathrm{O}} X \xleftarrow[\substack{\text { (ii) } \mathrm{Zn}+\mathrm{H}_2 \mathrm{O}}]{\text { (i) } \mathrm{O}_3} Y$$

Consider the following reaction sequence

$ \text { 2-methylpropane } \xrightarrow{\mathrm{KMnO}_{4}} X \xrightarrow[358 \mathrm{~K}]{20 \% \mathrm{H}_3 \mathrm{PO}_4} Y \xrightarrow[\text { (ii) } \mathrm{Zn} / \mathrm{H}_{2} \mathrm{O}]{\text { (i) } \mathrm{O}_{3}} A+B \text {. } $

What are $A$ and $B$ ?

What are $Y$ and $Z$ respectively in the given reaction sequence?

Which of the following is an example of electrophilic substitution reaction?

An alkene $X$ on ozonolysis gives a mixture of simplest ketone $(Y)$ and 3-pentanone. The IUPAC name of the alkene $X$ is

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.

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

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

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

$$\left(\mathrm{CH}_3\right)_3 \mathrm{CH} \xrightarrow{\mathrm{KMnO}_4} X \xrightarrow[573 \mathrm{~K}]{\mathrm{Cu}} Y$$

The number of $s p^3$ and $s p^2$ carbons in $Y$ are respectively

Arrange the following in decreasing order of their boiling points

(A) 2-methylbutane

(B) 2, 2-dimethyl propane

(C) Pentane

(D) Hexane

An alkyne has the molecular formula $\mathrm{C}_6 \mathrm{H}_{10}$. The number of 1 -alkyne isomers (excluding stereoisomers) possible for it is

' $X$ ' 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?

$$\begin{aligned} &\text { What are } X \text { and } Y \text { in the following reaction sequence? }\\ &\mathrm{C}_5 \mathrm{H}_{12} \mathrm{O} \xrightarrow[573 \mathrm{~K}]{\mathrm{Cu}} \mathrm{C}_5 \mathrm{H}_{10} \xrightarrow[\text { (ii) } \mathrm{Zn}+\mathrm{H}_2 \mathrm{O}]{\text { (i) } \mathrm{O}_3} X+Y \end{aligned}$$

Chlorobenzene when subjected to fittig reaction gives a compound ' $X$ '. The sum of $\sigma$ and $\pi$ - bonds in $X$ is

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 $Z$ ?