Based on condensed structural formulas, which of the following compounds is an alcohol? a.
CH3CH2COOH b. CH,CH2OCH3 1. c. CH,CH,CH,OH d. CH CH CHO Which of the following
molecules is not linear? a. H20 b. ??2 2. ?. ?? ?? d. Clh What is the approximate value of the H-
C-H bond angles in methane, CHA? a. 90° b. 109° 3. c. 120° d. 180° 4. What is the
approximate H-C-O bond angle in formaldehyde, H2C 0? a. 90° b. 109° C. 120° d. 180°
5. Which of the following molecules has a molecular dipole? CI Cum a. 1 b. 2 6. Which of the
following Newman projections represents the most stable conformation of 2,3- dimethylbutane?
CH3 CH3 CHa CHs CH3 H3C CH3 CH3 CH3 CH3 CH3 a. 1 b. 2 c. 3 d. 4
Solution
1) alcohol contains an OH functional group so option C
2) H2O has bent shaped molecule so option a
3) CH4 has tetrahedral shape so bond angle is 109 so option b
4) it's 120 so option c
5) option b because there is electronegativity difference beg3 carbon and chlorine which gives
permanent dipole to the molecule . In option 3 also dipole moment created in one direction will
be cancelled by the opposite direction. So option b is the right ans.
6)option c because in this the bulky methyl groups are present on opposite sides and thus
creating minimum repulsion.