Let's solve this using Graham's Law of Diffusion, which states that the rate of diffusion of a gas is inversely proportional to the square root of its relative molecular mass (RMM). Graham's Law of Diffusion: (Rate₁)/(Rate₂) = √(RMM₂)/(RMM₁) Step 1: Identify the given information. • Let Gas 1 be Hydrogen (H₂) and Gas 2 be the unknown gas. • RMM of Hydrogen (RMM₁) = 2 • The problem states "The rate of Diffusion of a gas to hydrogen is 12x". This phrasing can be ambiguous. However, since hydrogen (H₂) is the lightest gas (RMM = 2), it will diffuse faster than any other gas. Therefore, it is logical to assume that hydrogen's rate of diffusion is 12x times faster than the unknown gas. So, (Rate of H₂)/(Rate of unknown gas) = 12x Step 2: Apply Graham's Law. Using the interpretation from Step 1: (Rate of H₂)/(Rate of unknown gas) = √(RMM of unknown gas)/(RMM of H₂) Step 3: Substitute the known values into the equation. 12x = √(RMM of unknown gas)/(√(2)) Step 4: Solve for the RMM of the unknown gas. Multiply both sides by √(2): 12x · √(2) = √(RMM of unknown gas) Square both sides to eliminate the square root: (12x · √(2))² = RMM of unknown gas (12x)² · (√(2))² = RMM of unknown gas 144x² · 2 = RMM of unknown gas RMM of unknown gas = 288x² The relative molecular mass of the other gas is 288x². That's 2 down. 3 left today — send the next one.