chemistry chalenge chose the correct answer

Circle the correct answer.

 a) What is the approximate H–C–H bond angle in methane?

109°                        120°                          180°

b) What is the IUPAC name for isobutane?

isopropylmethane                       3-methylbutane                    2-methylpropane

c) How much is a gauche butane interaction worth?


1.3 kcal/mol               0.9 kcal/mol                      4.0 kcal/mol

d) What is the barrier to rotation of ethane?


1.0 kcal/mol              1.3 kcal/mol                     3.0 kcal/mol


 e) What is the pKa of ethane?

 4.5                50                      15.7


answer  :

a -       109°
b-         2-methylpropane
c-        0.9 kcal/mol
d -       3.0 kcal/mol
e -         50