It is because \(\mathrm{CH}_2=\mathrm{CH} \mathrm{C} \stackrel{\oplus}{\mathrm{H}}{ }_2 \longleftrightarrow \mathrm{CH}_2-\mathrm{CH}=\mathrm{CH}_2\) allyl carbocation is stabilized by resonance more than \(\mathrm{CH}_3-\mathrm{CH}_2 \stackrel{\oplus}{\mathrm{CH}_2}\) by inductive effect.

\(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_3<\mathrm{CH}_3 \mathrm{OCH}_3<\mathrm{CH}_3 \mathrm{CHO}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}\) Stronger the attractive forces, higher is the boiling point. Hydrocarbons are non-polar having weakest attractive forces, ethers are polar and aldehydes have strong dipolar interaction. Alcohols have maximum intermolecular forces due to the presence of H-bonding.

Henry's Law: It states that the partial vapour pressure of gas in vapour phase(g) is directly proportional to the mole fraction of the gas in the solution.
Applications of Henry's Law:
(i) To minimise the painful effects accompanying the decompression of deep sea divers, oxygen diluted with less soluble helium gas is used as breathing gas.
(ii) To increase the solubility of CO₂ in soft, drinks and soda water, the bottle is sealed under high pressure.

It is the extra pressure which must be applied on solution side so as to prevent the flow of solvent molecules from solution through semi-permeable

(i)
 
(ii)
 
(iii)
 
(iv)

Two methods can be employed for this preparation
(i) Via Williamson's synthesis

\(\underset { n-Butylchloride }{ { CH }_{ 3 }{ CH }_{ 2 }{ CH }_{ 2 }{ CH }_{ 2 }CI } +KOH(alc.)\overset { \triangle }{ \longrightarrow } \underset { But-l-ene }{ { CH }_{ 3 }{ CH }_{ 2 }CH={ CH }_{ 2 }+KCI+{ H }_{ 2 }O } \)

\((iv)\quad { 2CH }_{ 3 }Br+2Na\overset { Dry\quad ether }{ \underset { \quad Wurt\\ reaction }{ \longrightarrow } } \underset { Ethane }{ { CH }_{ 3 }{ CH }_{ 3 } } +2NaBr\)
\(\\ (vi)\quad \underset { Methyl\\ chloride }{ { CH }_{ 3 }CI } +KCN\longrightarrow \underset { Methyl\\ chloride }{ { CH }_{ 3 }CN } +KCI\)

(i) Mole fraction: It is the ratio of the number of moles of one component to the total number of moles of all the components present in the solution. For example, if a binary solution has n_A moles of one component and n_B moles of second component, then mole fraction of component A(x_A) and B(x_B) is:
\({ x }_{ A }=\frac { { n }_{ A } }{ { n }_{ A }+{ n }_{ B } } \) and \({ x }_{ B }=\frac { { n }_{ B } }{ { n }_{ A }+{ n }_{ B } } \) and x_A + x_B = 1
(ii) Molality: It is the number of moles of solute dissolved per 1000 g (or 1 kg) of solvent. If n₂ moles of solute are dissolved in w₁ g of solvent, then
Molality = \(\frac { { n }_{ 2 } }{ { w }_{ 1 } } \times 1000\)
(iii) Molarity: It is the number of moles of solute dissolved per liter of the solution. If n₂ moles of solute are dissolved in V mL of the solution, then
Molarity = \(\frac { { n }_{ 2 }\times 1000 }{ V } \)
(iv) Mass percentage: It is the amount of solute (in grams) per 100 g of the solution. If w₂ g of solute are dissolved in w₁ g of solvent, then
Mass percentage of solute = \(\frac { { w }_{ 2 } }{ { w }_{ 1 }+{ w }_{ 2 } } \times 100\)

In process of rusting, water molecules present at the layer of iron react with oxides and get dissociated and give H⁺ ions
H₂O + CO₂ → H₂CO₃
H₂CO₃↔  2H⁺  + CO₃^2–
In present of H⁺ ions iron convert in Fe2+ so this part is act as anode
Reaction at anode:
Fe(s) → Fe²⁺(aq) + 2e^–
Electron released at anodic spot move through the metals and go to another spot on the metal and reduce oxygen this spot act as cathode
Reaction at Cathode:
O₂(g) +  4H⁺(aq)  +  4e⁺( aq)  →   2H₂O(l)
The overall reaction
2Fe(s)  + O₂(g) + 4H⁺(aq) →  2H₂O(l)  + Fe²⁺(aq)
Hence, rusting of iron act as electrochemical cell.

\(\Delta_{\mathrm{r}} G^{\ominus}=-n F \mathrm{E}_{\text {(cell) }}^{\ominus}\) 
n in the above equation is 2, F = 96487 C mol ^–1 and \(\mathrm{E}_{\text {(cell })}^{\ominus}\) = 1.1 V
Therefore, \(\Delta_{\mathrm{r}} G^{\ominus}\) = – 2 × 1.1V × 96487 C mol ^–1
= – 21227 J mol^–1
= – 212.27 kJ mol^–1

(i)
 
S_N1 reaction proceeds via the formation of carbocation. The alkyl halide (I) is 3° while (II) is 2°. Therefore, (I) forms 3° carbocation while (II) forms 2° carbocation. Greater the stability of the carbocation, faster is the rate of S_N1 reaction. Since 3° carbocation is more stable than 2° carbocation. (I), i.e. 2-chloro-2-methylpropane, undergoes faster S_N1 reaction than (II) i.e., 3 chloropentane.
(ii)
 
The alkyl halide (I) is 2° while (II) is 1°. 2° carbocation is more stable than 1° carbocation. Therefore, (I), 2-chloroheptane, undergoes faster S_N1 reaction than (II), 1-chlorohexane.

Positive deviation from Raoult's law occurs when the total vapour pressure of the solution is more than corresponding vapour pressure in case of ideal solution. 
\(P={P}_{{A}}+{P}_{{B}}>{P}_{{A}}^{\circ} {X}_{{A}}+{P}_{{B}}^{\circ} {X}_{{B}}\)
Negative deviation from Raoult's law occurs when the total vapour pressure of the solution is less than corresponding vapour pressure in case of the ideal solution.
\({P}={P}_{{A}}+{P}_{{B}}<{P}_{{A}}^{\circ} {X}_{{A}}+{P}_{{B}}^{\circ} {X}_{{B}}\)
For positive deviation from Raoult's law, Δ _{mix ,}H has a positive sign.
For negative deviation from Raoult's law, Δ _{mix .}H has a negative sign.

Direct addition of H₂O to ethene in presence of an acid does not occur. Indirectly, ethene is first passed through cone. H₂SO₄, when ethyl hydrogen sulphate is formed.

Ethyl hydrogen sulphate when boiled with water undergoes hydrolysis to form ethanol.

(i) The cell walls of the vegetables have semi-permeable membrane. When the vegetables have dried, the concentration of water inside becomes low. When the dried or shrinked vegetables are placed in water, water enters into the cells due to osmosis. Hence, they swell and return to the original form.
(ii) The process is osmosis. It is defined as the flow of the solvent molecules from the solvent to the solution or from less concentrated solution to a more concentrated solution through a semi-permeable membrane.
(iii) The process will be accelerated with increase of temperature because osmosis becomes faster with increase of temperature.

(i) It is due to higher molecular weight, more surface area more vav deer waals, forces of Attraction in C₂H₂Oh.
(ii) Phenol is the strongest acid than alcohol because phenoxide ion is more stable due to resonance than ethoxide ion.
(iii) It is because ethers are not associated with inter molecular H- bonding, whereas ethanol.

(c), esters having the same number of carbon atoms in the alkyl and acyl group, i.e., CH₃CH₂ and COCH₃ group in CH₃CH₂OCOCH_3.

Methanol being more volatile than water, the solution of methanol in water will have more vapour pressure than water (a case of positive deviation).

(a) 1,0 M KCI solution because it will have more number of ions per unit volume of solution.
(b) \(2 \mathrm{H}^{+}+2 e^{-} \rightarrow \mathrm{H}_{2}(g)\)
\(\left[\because \mathrm{E}_{\mathrm{H}^{+} / \mathrm{H}_{2}}^{\circ}=0\right.\) , is higher than \(\left.\mathrm{E}_{\mathrm{Na}^{+} / \mathrm{Na}}^{\circ}=-2.71 \mathrm{~V}\right]\)
(c) When E_extemal > E^o _cell
(d) Mg(s) I Mg²⁺ (aq) II Ag⁺ (aq) I Ag(s)
\(\mathrm{E}_{\mathrm{cell}}=\mathrm{E}_{\text {cell }}^{\circ}-\frac{0.0591}{2} \log \frac{\left[\mathrm{Mg}^{2+}\right]}{\left[\mathrm{Ag}^{+}\right]^{2}}\)
(e) Silver wire at 30°C. Metallic conductance decreases with increase in temperature.
(f) \(\triangle\)G^o = - nPF = - 2 x l.05 V x 96500 C = - 202.65 kJ
W_max= - \(\triangle\)G^o =  - (-202.65 kJ) = + 202.65 kJ
(g) Mercury cell

(i) (c):


It has 9 C-atoms.
(iii) (b): Sodium phenoxide when heated with CO₂ at 400 K under a pressure of 4-7 atm followed by acidification gives 2-hydroxybenzoic acid (salicylic acid) as the main product along with a small amount of 4-hydroxybenzoic acid. This reaction is called Kolbe's reaction.

Salol is used as an intestinal antiseptic.

(i) (c) : Allylic chlorides are most reactive.
(ii) (c): 2⁰ - alkyl halides undergo hydrolysis by S_N1 or S_N2 mechanism.
(iii) (a): Smaller the size of the nucleophile (i.e., CH₃O^-), more reactive it is.
(iv) (d): Stearic hindrance due to bulky alkyl groups prevents the attack of the nucleophile in S_N2 mechanism.

(i) (d) : II represents negative deviations and III represents positive deviations.
(ii) (b): For positive deviations \(p_{A}>p_{A}^{\circ} x_{A} \text { and } p_{B}>p_{B}^{\circ} x_{B}\)
(iii) (b): Water and nitric acid mixture shows negative deviations from Raoult's law, hence \(p_{A}<p_{A}^{\circ} x_{A} \text { and } p_{B}<p_{B}^{\circ} x_{B}\)
(iv) (d): Water-HCl mixture shows negative deviations from Raoult's law and solutions showing negative deviations from ideal behaviour form maximum boiling azeotrope.