An organic compound crystallises in an orthorhombic cell in the ratio of 2:1. The dimensions of the cell are 12.05, 15.05 and 2.69 A and density is 1.419 g/cm3. Find molar mass of the compound.

Density (d)=Z×Ma3×NAAccording to question, the length,(l), width (w) and height (h) of orthorhombic cell are different.ah=12.05A=12.05×10−8cmal=15.05∘A=15.05×10−8cmaw=2.69A=2.69×10−8cmEach cell has 2 molecules Z=2 and NA=6.022×1023Hence, molar mass M=d×ah×aw×al×NAZ1.419×12.05×10−8×15.05×10−8=×2.69×10−8×6.023×10232=2084.6×10−1=209g/mol