Question

question 6
2 pts
the effectiveness of various metals in preventing rusting of iron.
description: several weeks after allen conducted a classroom experiment on the effectiveness of various metals in releasing hydrogen gas from hydrochloric acid, he read that the gas company was burying sheets of magnesium next to iron pipelines in order to prevent rusting. allen wondered if other active metals would also be effective in preventing rust.
to investigate, he placed each of the following into a separate test tube containing water: one iron nail; one iron nail wrapped with an aluminum strip; one iron nail wrapped with a magnesium strip; and one iron nail wrapped in a lead strip. he used the same amounts of water from the same source, equal amounts of the metal wraps and the same type of iron nails. at the end of five days, he described the amounts of rusting either as small, moderate or large. he also recorded the color of the water.
which of the following acts as the control group in this experiment?
the one iron nail wrapped in a lead strip.
the one iron nail wrapped with a magnesium strip.
the one iron nail.
the one iron nail wrapped with an aluminum strip.

Explanation:

In an experiment, the control group is the one that is not exposed to the variable being tested. Here, the variable is the presence of different metal wraps on the iron nail to prevent rusting. The iron nail without any metal wrap serves as the baseline for comparison.

Answer:

The one iron nail.