Chemistry

This problem tests whether you can identify both the reaction type and the correct product. The key insight is recognizing that when two substances combine to form one new compound, that's a combination reaction—and you need to balance charges correctly to write the right formula. Calcium is $\text{Ca}^{2+}$ and hydroxide is $\text{OH}^-$, so the product needs two hydroxide ions to balance the charge.

This problem tests whether you can identify both the reaction type and the correct product. The key insight is recognizing that when two substances combine to form one new compound, that's a combination reaction—and you need to balance charges correctly to write the right formula. Calcium is $\text{Ca}^{2+}$ and hydroxide is $\text{OH}^-$, so the product needs two hydroxide ions to balance the charge.