Download App

Alcohols, Phenols, and Ethers — Chemistry STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceChemistryAlcohols, Phenols, and Ethers3 Marks
Question
Give reasons -
(a) Ethanol has the a higher melting point than methoxy methane.
(b) Ethanol is easily soluble in water.
(c) Phenol is more stronger acid in comparison to alcohol.
✓

Answer

(a) Boiling Point (Ethanol vs. Methoxy methane): Ethanol $\left( CH _3 CH _2 OH \right)$ molecules are associated through intermolecular hydrogen bonding due to the presence of the polar - OH group. Methoxy methane $\left( CH _3 OCH _3\right)$ lacks this bonding and only has weak dipoledipole interactions. Consequently, more energy is required to break the hydrogen bonds in ethanol, giving it a higher boiling point.
(b) (b) Solubility of Ethanol in Water: Ethanol is easily soluble in water because it can form hydrogen bonds with water molecules. The hydroxyl $(- OH )$ group of ethanol interacts with the polar $H _2 O$ molecules, allowing them to mix uniformly.
(c) Acidity (Phenol vs. Alcohol): Phenol is a stronger acid than alcohol because the phenoxide ion formed after losing a proton is stabilized by resonance within the benzene ring. In contrast, the alkoxide ion ( $R-O^{-}$) formed by alcohols is destabilized by the $+I$ effect of the alkyl group, which concentrates the negative charge on the oxygen atom.

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 "3 Marks Question" from Alcohols, Phenols, and Ethers→Alcohols, Phenols, and Ethers — all question types→Chemistry STD 12 Science question papers→Bihar Board STD 12 Science question papers→Bihar Board question paper generator→

Similar questions

A graph between ln k and $\frac{1}{\text{t}}$ for a reaction is given. Here k is rate constant and T is temperature in Kelvin.

If OA = a and OB = b, answer the following:

  1. What is the activation energy (Ea) of the reaction?
  2. What is the frequency factor (A) for the reaction?

→
In the following cases rearrange the compounds as directed:

  1. In an increasing order of basic strength:

C6H5NH2, C6H5N(CH3)2, (C2H5)6NH and CH3NH2.

  1. In a decreasing order of basic strength:

Aniline, p-nitroaniline and p-toluidine.

  1. In an increasing order of pKb values:

C2H5NH2, C6H5 NHCH3, (C2H5)2NH and C6H5NH2.

→
Give the structures of A and B in the following sequence of reactions:
  1. $\text{CH}_3\text{COOH}\xrightarrow[\Delta]{\text{NH}_3\ \ \ }\text{A}\ \ \ \xrightarrow{\text{NaOBr}}\text{B}$
  2. $\text{C}_6\text{H}_5\text{No}_2\xrightarrow{\text{Fe}/ \text{ HCl}}\text{A}\ \ \ \ \ \xrightarrow[0^\circ-5^\circ\text{C}]{\text{NaNo}_2+\text{HCl}}\text{B}$
  3. $\text{C}_6\text{H}_5\text{N}_2^+\text{Cl}^{-}\xrightarrow[\Delta]{\text{CuCN}}\text{A}\ \ \ \ \xrightarrow{\text{H}_2\text{O}/\text{ H}^+}\text{B}$
→
A first order reaction takes 20 minutes for 25% decomposition. Calculate the time when 75% of the reaction will be completed. (Given : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)
→
Explain Crystal field splitting in tetrahedral complax.
→
In the button cells widely used in watches and other devices the following reaction takes place :
$Zn _{( s )}+ Ag _2 O _{( s )}+ H _2 O _{( l )} \rightarrow Zn _{( aq )}^{2+}+2 Ag _{( s )}+2 OH _{( aq )}^{-}$
Determine $\Delta_{ r } G ^{\circ}$ and $E ^{\circ}$ for the reaction.
→
Nalorphene $\left( C _{19} H _{21} NO _3\right)$, similar to morphine, is used to combat withdrawal symptoms in narcotic users. Dose of nalorphene generally given is 1.5 mg. Calculate the mass of $1.5 \times 10^{-3} m$ aqueous solution required for the above dose.
→
Calculate the mass of a non-volatile solute (molar mass 40 g mol–1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
→
The monoamino monocarboxylic acids have two pKa values.
→
Write down the IUPAC name for the following complex and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:
K[Cr(H2O)2(C2O4)2].3H2O
→