Which of the following molecules is chiral in nature?
Show Hint
- Propan-2-ol
- Butan-2-ol
- 1-Bromobutane
- 2-Bromopropane
The Correct Option is B
Solution and Explanation
A molecule is chiral if it lacks a plane of symmetry and contains at least one stereocenter (an asymmetric chiral carbon).
Step 2: Meaning
A chiral carbon must be $sp^3$ hybridized and bonded to four distinctly different chemical groups or atoms.
Step 3: Analysis
- (A) Propan-2-ol: C2 is attached to $-OH, -H,$ and two identical $-CH_3$ groups (achiral).
- (C) 1-Bromobutane: C1 is attached to $-Br,$ a propyl group, and two identical $-H$ atoms (achiral).
- (D) 2-Bromopropane: C2 is attached to $-Br, -H,$ and two identical $-CH_3$ groups (achiral).
- (B) Butan-2-ol: The C2 atom is attached to four distinct groups:
a methyl group ($-CH_3$), an ethyl group ($-CH_2CH_3$), a hydroxyl group ($-OH$), and a hydrogen atom ($-H$).
Step 4: Conclusion
Having four different groups attached to the central carbon makes Butan-2-ol a chiral molecule.
Final Answer: (B)
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 Chirality & symmetry of organic molecules with or without chiral centres Questions
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