In a balanced equation, 2Na + 2H₂O → 2NaOH + H₂, what mass of sodium hydroxide is produced when 4.6 g of sodium reacts completely? (Relative atomic masses: Na = 23, O = 16, H = 1)

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Question

In a balanced equation, 2Na + 2H₂O → 2NaOH + H₂, what mass of sodium hydroxide is produced when 4.6 g of sodium reacts completely? (Relative atomic masses: Na = 23, O = 16, H = 1)

Accepted Answer

B) 8.0 g — Moles of Na = 4.6 ÷ 23 = 0.20 mol. The molar ratio Na:NaOH is 2:2 = 1:1, so moles of NaOH = 0.20 mol. Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol. Mass of NaOH = 0.20 × 40 = 8.0 g. Option A uses the molar mass of oxygen instead of NaOH. Option C doubles the correct answer by using a 1:2 ratio. Option D gives the molar mass of NaOH rather than the mass produced.

Answer

B) 8.0 g

Answer

C) 16.0 g

Answer

D) 40.0 g

Answer

A) 4.0 g

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