Three treatments of different starting materials are listed:

\begin{tabular}{|l|l|}
\hline
Substance & Characteristics \\
\hline
1 & The substance was heated and then placed in an ice bath. \\
\hline
2 & \begin{tabular}{l} The substance was in a salt solution of 2 M and later placed in a \\ solution of 4 M to cause a reaction. \end{tabular} \\
\hline
3 & The substance was hammered and broken into pieces. \\
\hline
\end{tabular}

Which statement explains the treatments?

A. Substance 1 was activated by a decrease in temperature, Substance 2 was activated by the change in concentration, and Substance 3 decreased the surface area.

B. Substance 1 was activated by a decrease in temperature, Substance 2 was activated by the change in pressure, and Substance 3 increased the surface area.

C. Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in pressure, and Substance 3 decreased the surface area.

D. Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in concentration, and Substance 3 increased the surface area.



Answer :

Let's analyze each treatment and the corresponding characteristics step by step:

### Treatment 1:
- Substance 1 was heated and then placed in an ice bath.
- Heating generally activates a substance, and placing it in an ice bath subsequently inactivates it.
- Therefore, an appropriate characterization for Substance 1 is:
- "Substance 1 was activated by the heat and inactivated by ice."

### Treatment 2:
- Substance 2 was first placed in a solution of 2 M salt and later in a solution of 4 M salt to cause a reaction.
- The change from a lower concentration of salt (2 M) to a higher concentration of salt (4 M) signifies a reaction induced by the change in concentration.
- Therefore, an appropriate characterization for Substance 2 is:
- "Substance 2 was activated by the change in concentration."

### Treatment 3:
- Substance 3 was hammered and broken into pieces.
- Hammering and breaking a substance into pieces increases its surface area, allowing for potentially more effective interactions with other substances or reaction conditions.
- Therefore, an appropriate characterization for Substance 3 is:
- "Substance 3 increased the surface area."

Combining these explanations, we get the statement:

- "Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in concentration, and Substance 3 increased the surface area."

This matches the last option given in the question. Thus, the correct answer is:

Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in concentration, and Substance 3 increased the surface area.

This corresponds to statement number 4.