Which additional product balances the reaction H_2SO_4 + 2NaOH → Na_2SO_4 + ________?

• A. H_2O_2
• B. H_3O^+
• C. 2H_2O
• D. 2OH^−

Answer: (C)

Verified step by step guidance

1. Identify the type of reaction: This is an acid-base neutralization reaction where sulfuric acid (H_2SO_4), a strong acid, reacts with sodium hydroxide (NaOH), a strong base.
2. Write the reactants and known products: The reactants are H_2SO_4 and 2NaOH, and one product is sodium sulfate (Na_2SO_4). The other product is typically water in acid-base neutralizations.
3. Balance the sulfate ion: Since sulfuric acid has one sulfate ion (SO_4^{2-}) and sodium hydroxide provides sodium ions (Na^+), two NaOH molecules are needed to balance the sulfate ion, forming Na_2SO_4.
4. Balance hydrogen and oxygen atoms: The hydrogen ions (H^+) from H_2SO_4 combine with hydroxide ions (OH^-) from NaOH to form water (H_2O). Since there are 2 H^+ ions from H_2SO_4 and 2 OH^- ions from 2 NaOH, they form 2 molecules of water.
5. Write the complete balanced equation: H_2SO_4 + 2NaOH → Na_2SO_4 + 2H_2O, confirming that water is the additional product balancing the reaction.