1. **State the problem:** Determine if each given chemical reaction is an acid-base neutralization reaction. 2. **Recall the definition:** An acid-base neutralization reaction occurs when an acid reacts with a base to produce a salt and water. 3. **Analyze each reaction:** a) $\mathrm{H_2S + CuSO_4 \rightarrow H_2SO_4 + CuS}$ - $\mathrm{H_2S}$ is a weak acid. - $\mathrm{CuSO_4}$ is a salt, not a base. - Products are $\mathrm{H_2SO_4}$ (acid) and $\mathrm{CuS}$ (salt). - No base present, so **not** an acid-base neutralization. b) $\mathrm{HCN + LiOH \rightarrow LiCN + H_2O}$ - $\mathrm{HCN}$ is a weak acid. - $\mathrm{LiOH}$ is a strong base. - Products are $\mathrm{LiCN}$ (salt) and $\mathrm{H_2O}$ (water). - Acid + base producing salt and water means **acid-base neutralization**. c) $\mathrm{H_2SO_4 + Ba(OH)_2 \rightarrow BaSO_4 + 2H_2O}$ - $\mathrm{H_2SO_4}$ is a strong acid. - $\mathrm{Ba(OH)_2}$ is a strong base. - Products are $\mathrm{BaSO_4}$ (salt) and water. - Acid + base producing salt and water means **acid-base neutralization**. d) $\mathrm{Ni + 2HCl \rightarrow NiCl_2 + H_2}$ - $\mathrm{Ni}$ is a metal, not a base. - $\mathrm{HCl}$ is a strong acid. - Products are $\mathrm{NiCl_2}$ (salt) and hydrogen gas. - No base involved, so **not** an acid-base neutralization. **Final answers:** - a) No - b) Yes - c) Yes - d) No