Which is the correct order of acid strength from the following?
Show Hint
- C$_6$H$_5$OH > H$_2$O > ROH
- C$_6$H$_5$OH > ROH > H$_2$O
- ROH > C$_6$H$_5$OH > H$_2$O
- H$_2$O > C$_6$H$_5$OH > ROH
The Correct Option is D
Solution and Explanation
To solve this problem, we need to compare the acidity of phenol (C6H5OH), alcohol (ROH), and water (H2O).
1. Understanding Acid Strength:
Acid strength depends on the ability of the molecule to donate a proton (H+). This is determined by the stability of the conjugate base formed after proton loss.
2. Phenol (C6H5OH) vs Alcohol (ROH):
Phenol is more acidic than alcohol because the negative charge on the oxygen in the phenoxide ion (C6H5O-) is stabilized by resonance with the aromatic ring. In contrast, the negative charge on the oxygen in the alkoxide ion (RO-) is not stabilized, making alcohol less acidic than phenol.
3. Phenol (C6H5OH) vs Water (H2O):
Water (H2O) is a weaker acid than phenol. Although water can donate a proton to form the hydroxide ion (OH-), the conjugate base of phenol is more stable due to resonance stabilization.
4. Conclusion:
The correct order of acid strength is: Water > Phenol > Alcohol.
Final Answer:
The correct option is (D) H2O > C6H5OH > ROH.
Top CBSE CLASS XII Chemistry Questions
- ${AgNO_3}$ does not decompose where :
- Azeotropic mixture of water and HCl boils at 381.5 K. By distilling the mixture it is possible to obtain
Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylanilineAccount for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Top CBSE CLASS XII Carboxylic Acids Questions
- Assertion (A): The pK$_a$ of O$_2$N–CH$_2$–COOH is lower than that of CH$_3$–COOH. Reason (R): The –NO$_2$ group shows an electron-withdrawing effect, which increases the acidic character of O$_2$N–CH$_2$–COOH.
- Complete the following reaction: \[ \text{C}_6\text{H}_5\text{N}_2^+Cl^- \xrightarrow{\text{(i) HBF}_4} \xrightarrow{\text{(ii) NaNO}_2/\text{Cu}, \Delta} \quad ? \]
- Write the structures of A and B in the following reaction: \[ \text{C}_6\text{H}_5\text{COOH} \xrightarrow{\text{NH}_3, \Delta} A \xrightarrow{\text{Br}_2/\text{NaOH}} B \]
- Assertion (A): Benzoic acid does not undergo Friedel – Crafts reaction.
Reason (R): Carboxyl group is deactivating and the catalyst aluminium chloride gets bonded to the carboxyl group. - Which one of the given compounds is a stronger acid and why?
CH$_2$FCH$_2$COOH or CH$_3$CHFCH$_2$COOH
Top CBSE CLASS XII Questions
- 2, b, c are in A.P. and the range of determinant $\begin{vmatrix}1&1&1\\ 2&b&c\\ 4&b^{2}&c^{2}\end{vmatrix}$ is [2, 16]. Then find range of c is
- A boy of mass 50 kg is standing at one end of a, boat of length 9 m and mass 400 kg. He runs to the other, end. The distance through which the centre of mass of the boat boy system moves is
- A capillary tube of radius r is dipped inside a large vessel of water. The mass of water raised above water level is M. If the radius of capillary is doubled, the mass of water inside capillary will be
- A circular disc is rotating about its own axis. An external opposing torque 0.02 Nm is applied on the disc by which it comes rest in 5 seconds. The initial angular momentum of disc is
- A circular disc is rotating about its own axis at uniform angular velocity \(\omega.\) The disc is subjected to uniform angular retardation by which its angular velocity is decreased to \(\frac {\omega}{2}\) during 120 rotations. The number of rotations further made by it before coming to rest is