Metal has an fcc lattice. The edge length of the unit cell is 404 pm. The density of the metal is 2.72 g cm⁻³. The molar mass (in g mol⁻¹) of the metal is: [Avogadro's constant = NA = 6.02 × 10²³ mol⁻¹]

The formula for the density of the metal is as given below:
d = Z × M / (V × NA)
Substituting values in the above expression, we get
2.72 = 4 × M / ((4.04 × 10⁻⁸)³ × 6.02 × 10²³)
M = 2.72 × (4.04)³ × 6.02 × 10⁻¹⁶
M = 27 g/mol
Hence, the molar mass of the metal is 27 g/mol.
Hence, the correct option is C