Consider the e2 elimination of 3‑bromopentane with hydroxide. the starting material consists of a chiral carbon with an in plane bond to bromine pointing to the upper left, an in plane bond to ethyl pointing to the right, a wedged bond to ethyl pointing to the lower left and a dashed bond to hydrogen pointing to the lower left. this reacts with hydroxide to form the product, water and bromide ion. complete the curved arrow electron-pushing mechanism and draw the structure of the organic product formed.

Scheme is attached

Explanation:

When 3‑bromopentane reacts with hydroxide, (Z)-pent-2-ene will produce through E 2 (Z)-pent-2-ene.

Mechanism

Hydroxide ion (OH⁻ ) is a strong nucleophile so it abstract the proton from carbon next to the carbon attached with bromine.

The the carbon next to carbon of bromine gets -ve charge, mean while it shares its electrons with the carbon having bromine and make a double bond.

As bromine  is a good leaving group so it easily gets detached from carbon, so that carbon comes to its normal state.

As a result (Z)-pent-2-ene will produce. we call it Z because mostly trans products will form.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.