Indicate whether each reaction is a redox reaction. If it is, which atom gets oxidized and which atom gets reduced? Consult the shortcut rules. \(\mathrm{Ca}+2 \mathrm{H}^{+} \rightarrow \mathrm{Ca}^{2+}+\mathrm{H}_{2}\)

The given chemical reaction is: \(\mathrm{Ca} + 2 \mathrm{H}^+ \rightarrow \mathrm{Ca}^{2+} + \mathrm{H}_{2}\)

To determine if the given chemical reaction is a redox reaction, we must first assign oxidation numbers to each atom in the reactants and products: - For elements in their elemental form, the oxidation number is 0. - For monatomic ions, the oxidation number is equal to the charge on the ion. - For hydrogen, the oxidation number is usually +1, except in metal hydrides where it is -1. In the reactants: - Calcium (Ca) is in its elemental form, so its oxidation number is 0. - Hydrogen (H) is in the form of \(\mathrm{H^+}\) ions, so its oxidation number is +1. In the products: - Calcium is in the form of \(\mathrm{Ca^{2+}}\) ions, so its oxidation number is +2. - Hydrogen is in the form of \(\mathrm{H_2}\) molecule, so its oxidation number is 0.

Now, we will compare the oxidation numbers of the atoms in the reactants and the products: - Calcium (Ca) has an oxidation number change from 0 to +2. Since its oxidation number increased, it gets oxidized. - Hydrogen (H) has an oxidation number change from +1 to 0. Since its oxidation number decreased, it gets reduced.

The given chemical reaction \(\mathrm{Ca} + 2 \mathrm{H}^+ \rightarrow \mathrm{Ca}^{2+} + \mathrm{H}_2\) is a redox reaction. In this reaction, the Calcium (Ca) atom gets oxidized (from 0 to +2 oxidation state), and the Hydrogen (H) atom gets reduced (from +1 to 0 oxidation state).