Look at the reaction. cap h sub 2 SO sub 4 A q plus Ca OH sub 2 A q rightarrow CaSO sub 4 times A q plus 2 cap h sub 2 cap o l Which substance is the base in the reaction?

A base accepts hydrogen ions or produces hydroxide ions in solution. Ca(OH)₂ contains hydroxide ions, OH⁻, and reacts with the acid H₂SO₄ to form a salt and water. Therefore, the base is Ca(OH)₂, choice A.

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