Important Questions for Class 12 Chapter 12 - Aldehydes, Ketones and Carboxylic Acids

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Important questions based on NCERT syllabus for Chapter 12 - Aldehydes, Ketones and Carboxylic Acids:

Question-1: Arrange the following compounds in increasing order of their boiling points:
CH3CHO, CH3CH2OH ,CH3OCH3, CH3CH2CH3

Solution: The order is : CH3CH2CH3 < CH3OCH3 < CH3CHO <CH3CH2OH
All these compounds have comparable molecular masses CH3CH2OH undergoes extensive intermolecular Il-bonding and thus its b.pt. is the highest. CH3CHO is more pdlar than CH3OCH3 so that dipole-dipoie interactions in CH3CHO are greater than in CH3OCH3. Thus, b.pt. of CH3CHO > CH3OCH3. CH3CH2CH3 has only weak van der waals forces between its molecules and hence has the lowest b.pt.

Question-2: Name the following compounds according to IUPAC system of nomenclature:
(i) CH3CH (CH3)—CH2 CH2—CHO (ii) CH3CH2COCH(C2H5)CH2CH2Cl (iii) CH3CH=CHCHO (iv) CH3COCH2COCH3
(v)CH3CH(CH3)CH2C(CH3)2COCH3
(vi)(CH3)3CCH2COOH.
(vii)OHCC6H4CHO-p

Solution: (i)4-Methyl pentanal
(ii)6-Chloro-4-ethylhexan-3-one
(iii)But-2-en-l-al
(iv)Pentane-2,4-dione
(v)3,3,5-Trimethyl-hexan-2-one
(vi)3,3-Dimethyl butanoic acid
(vii)Benzene-1,4-dicarbaldehyde

Question-3: Give the 1UPAC names of the following compounds:
(i)PhCH2CH2COOH
(ii)(CH3)2 C=CHCOOH

Solution: (i) 3 – Phenylpropanoic acid
(ii) 3 – Methylbut-2-enoic acid