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Hydrogen gas can be produced by the reaction of sodium metal with hydrochloric a

ID: 891280 • Letter: H

Question

Hydrogen gas can be produced by the reaction of sodium metal with hydrochloric acid. The reaction between the acid and the sodium is: 2Na (s) + 2 HCl (aq) 2NaCl(aq) + H2 (g) A student collected 12.0 L of H2(g) gas over water at 20.0 °C and at a total pressure of 735 mmHg.

a. What is the pressure of dry H2 gas? (Hint: Vapour pressure of water at 20.0°C is 17.5 mmHg)

b. Calculate the mass of sodium is required to form 12.0 L of H2.

Identify which species is the oxidizing agent and which is the reducing agent.

Oxidizing agent:___

Reducing agent:___

Explanation / Answer

2Na (s) + 2 HCl (aq) -----> 2NaCl(aq) + H2 (g)

Collected 12L of H2

Temperature = 293K

Pressure total = 735 mm of Hg = 0.967 atm

Vapour pressure of dry H2 gas = 735-17.5 = 717.5 mm of Hg

12L of H2 = 12 moles of H2

Therefore 2 moles Of Na produces 1 mole of H2

so 24 moles of Na are required for 12L of H2

mass = 24*23 = 552 grams

Oxidiszing agent = HCl

reducing agent = Na