In chemistry we did a lab examining iron nails corroding in agar. one of the nails was wrapped in zinc, and the nail did not rust. a whitish substance appeared around the nail, what is the whitish substance?

Zn(OH)₂

Explanation:

Zn is above Fe in the activity series, so it is more readily oxidized:

Zn(s) ⟶ Zn²⁺(aq) + 2e⁻

The zinc ions go into solution.

The electrons travel from the Zn to the surface of the iron nail, where they reduce the water to hydrogen and hydroxide ions.

2H₂O(ℓ) + 2e⁻ ⟶ H₂(g) + 2OH⁻(aq)

Neither the zinc ions nor the hydroxide ions can move far through the gel.

Their concentration builds up around the hail. The ions find each other and form a precipitate.

Zn²⁺(aq) + 2OH⁻(aq) ⟶  Zn(OH)₂(s)

explanation:

crosscutting concepts have application across all domains of science. as such, they are a way of linking the different domains of science. they include patterns; cause and effect; scale, proportion, and quantity; systems and system models; energy and matter; structure and function; and stability and change.