2. The minimized structure of phenacetin is planar, and the chemical shifts of the aromatic protons in the NMR spectrum can be rationalized by electron delocalization. When drawn in the planar conformation, are any of the aromatic protons related by a valid symmetry operation? Explain why the resonances in the aromatic region produce two doublets instead of more complex splitting patterns.

Explanation:

Reason for the aromatic region shows two doublets:

1. Two types of protons present in the aromatic ring (Ha & Hb protons) based on their environment.

2. Two doublets are respectively shown to the two Ha protons in the ortho position and the two Hb protons in the meta position from the amide group.

3. Two Ha protons are coupled with two Hb protons.  

Summary: Two sets (Ha & Hb) of two equivalent protons (4 protons) present in the aromatic ring of Phenacetin. Two Ha protons are coupled with two Hb protons hence in the aromatic region two doublets are observed,

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

gas

explanation:

smoke is the matter of a gas