consider the following reaction

Ca + 2HCI CaCl2 +h2
identify the substance that is oxidized
identify the substance that is reduced
identify that is oxidizing agent
identify the reducing agent

Oxidation is loss of electrons.

Reduction is gain of electrons.
The material oxidized is the reducing agent.
The material reduced is the oxidizing agent.

Oxidizing agents remove electrons.

Reducing agents donate electrons.

Cl takes away electrons from Ca as seen in the product.

Cl^- doesn't take away anything but H^+ does.

chemistry

To determine the substance that is oxidized and reduced, as well as the oxidizing and reducing agents in a chemical reaction, we need to assign oxidation numbers to each element or compound in the reaction. Oxidation numbers represent the hypothetical charge that an atom would have if all its bonds were 100% ionic.

In the given reaction:

Ca + 2HCl → CaCl2 + H2

1. Identify the substance that is oxidized:
To identify the substance that is oxidized, we need to look for the element or compound whose oxidation number increases in the reaction. In this case, the oxidation number of calcium (Ca) changes from 0 to +2. Since the oxidation number of calcium increases, calcium is the substance that is oxidized.

2. Identify the substance that is reduced:
To identify the substance that is reduced, we need to look for the element or compound whose oxidation number decreases in the reaction. In this case, the oxidation number of hydrogen (H) changes from +1 to 0 (in H2). Since the oxidation number of hydrogen decreases, hydrogen is the substance that is reduced.

3. Identify the oxidizing agent:
The oxidizing agent is the substance that causes another substance to be oxidized by undergoing reduction itself. In this case, HCl is the oxidizing agent. It donates its chlorine atom to calcium, causing calcium to be oxidized.

4. Identify the reducing agent:
The reducing agent is the substance that causes another substance to be reduced by undergoing oxidation itself. In this case, Ca is the reducing agent since it loses electrons to chlorine, causing chlorine to be reduced.

In summary:
- Substance oxidized: Calcium (Ca)
- Substance reduced: Hydrogen (H)
- Oxidizing agent: Hydrochloric acid (HCl)
- Reducing agent: Calcium (Ca)

Please note that the information provided above assumes the oxidation numbers assigned based on the general rules of assigning oxidation numbers. It is always a good practice to verify the oxidation numbers using electronegativity differences and the known rules for assigning oxidation numbers.