Central Board Of Secondary Education – ( CBSE )
Class – 11
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Recommended Question & Answers for Class 11
1. Which of the following relations are functions? Give reasons. If it is a function, determine its domain and range. ?
{(2, 1), (5, 1), (8, 1), (11, 1), (14, 1), (17, 1)}
Since 2, 5, 8, 11, 14, and 17 are the elements of the domain of the given relation having their unique images, this relation is a function.
Here, domain = {2, 5, 8, 11, 14, 17} and range = {1} {(2, 1), (5, 1), (8, 1), (11, 1), (14, 1), (17, 1)}
2. Which of the following represents the correct TUPAC name for the compounds concerned?
(b) 2, 4, 7-Trimethyloctane or 2, 5, 7- Trimethyloctane
(c) 2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane
(d) But-3-yn- l-ol or But-4-ol-yne.
Answer:
(a) 2, 2-Demethylpentane
(b)2, 4, 7-Trimethyloctane. For two alkyl groups on the same carbon its locant is repeated twice, 2, 4, 7-locant set is lower than 2, 5, 7.
(c) 2- Chloro-4-methylpentane. Alphabetical order of substituents,
(d) But-3-yn-l-ol. Lower locant for the principal functional group, i.e., alcohol.
3. At 0°C, the density of a gaseous oxide at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?
Using the expression, d =MP/RT , at the same temperature and for same density,
M1P1 = M2P2 (as R is constant)
(Gaseous oxide) (N2)
or
M1 x 2 = 28 x 5(Molecular mass of N2 = 28 u)
or M1 = 70u