3-Chlorocyclopropene, on treatment with AgBF4, gives a precipitate of AgCl and a stable solution of a product that shows a single 1H absorption at 11.04 ppm. What is a likely structure for the product?

check attached picture.

Explanation:

NB: please check attached picture for the drawings.

Chemical shift occurs as a result of shielding and de-shielding which causes the position of the NMR signals to shift. And, the shifts are caused by the involvement of electrons in chemical bonds. Chemical shifts are measured in Hertz that is, cycles per second. The standard compound used for this purpose is tetramethylsilane.

Looking at the question, 3-Chlorocyclopropene is reacted with AgBF4 and it gives precipitate of AgCl and a stable solution of a product. The question now says that the product shows a single 1H absorption at 11.04 ppm.

The Nuclear Magnetic Resonance (NMR) spectroscopy, H'NMR which is 11.04 ppm indicates aromaticity. And one single 1H equal atoms of hydrogen is because of the Resonance effect.

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.