Question

Consider the formation of hcn by the reaction of nacn (sodium cyanide) with an acid such as h2so4 (sulfuric acid): 2nacn(s)+h2so4(aq)âna2so4(aq)+2hcn(g) what mass of nacn gives the lethal dose in the room?

Answer 1

Answer:

18.0 g

Explanation:

There is some info missing. I think this is the original question.

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is approximately 300 mg HCN per kilogram of air when inhaled. The density of air at 26 °C is 1.18 kg/m³.

Consider the formation of HCN by the reaction of NaCN (sodium cyanide) with an acid such as H₂SO₄ (sulfuric acid):

2 NaCN(s) + H₂SO₄(aq) → Na₂SO₄(aq) + 2 HCN(g)

What mass of NaCN gives the lethal dose in the 28.0 m³ room? Express your answer to three significant figures and include the appropriate units.

The density of air is 1.18 kg/m³. The mass represented by 28 m³ is:

28.0 m³ × (1.18 kg/m³) = 33.0 kg

The lethal dose is approximately 300 mg HCN per kilogram of air. The lethal dose of HCN in 33.0 kg of air is:

33.0 kg air × (300 mg HCN / 1 kg air) = 9900 mg HCN = 9.90 g HCN

From the balanced equation, we can establish the following relations:

• The molar mass of HCN is 27.03 g/mol.
• The molar ratio of HCN to NaCN is 2:2.
• The molar mass of NaCN is 49.01 g/mol.

The mass of NaCN that produces 9.90 g of HCN is:

$9.90gHCN.\frac{1molHCN}{27.03gHCN} .\frac{2molNaCN}{2molHCN} .\frac{49.01gNaCN}{1molNaCN} =18.0gNaCN$

Answer 2

2NaCN(s) + H₂SO₄(aq) --> Na₂SO₄(aq) + 2HCN(g)  

The molar ratio between NaCN : HCN is 2:2  or 1:1

Mass of HCN = 16.7 g

Molar mass of HCN = 1 + 12 + 14 = 27 g/mol

Molar mass of NaCN = 49 g/mol

Therefore, the mass of NaCN is

16.7 g of  HCN x 49 g/mol of NaCN / 27 g/mol of HCN = 30.3 grams of NaCN

Therefore, 30.3 grams of NaCN gives the lethal dose in the room.