How do stimuli (ph, temperature, heat, anything that causes the hydrogel to change) cause hydrogels to change?

Iknow #2 is d. i just need to know why

In the following redox reaction which is the oxidizing agent and which is the reducing agent? alcl3 + na nacl + al oxidizing agent = reducing agent =

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)