If a lab group were using hydrochloric acid to perform a substitution reaction, which precaution would not be a concern?

A Flammability

Explanation:

A Flammability

B Health

C Reactivity

D Contact

Hydrochloric acid will not burn under normal fire conditions.

A substitution reaction is one in which an element or atom in a compound is displaced or substituted by another atom in the course of the reaction.

Hydrochloric acid is a strong and highly reactive acid that has the ability to burn solid substances that come in contact with it. Hence, it posses a health risk when the fumes are inhaled or when it gets in contact with the skin.

Hydrochloric acid is highly reactive and considered as a strong oxidizing agent. It has the capacity to react with several metals to liberate hydrogen gas, reacts with carbonate compounds to liberate carbon dioxide gas, etc.

However, hydrochloric acid is not flammable and therefore, will not burn under normal fire conditions.

The correct option is A.

a chemical reaction happens

explanation:

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.