29.2% (w/W) HCI stock solution has density of 1.25 g mL-1. The molecular weight of HCI is 36.5 mol-1. The volume (mL) of stock solution required to prepare a 200 mL solution 0.4 M HCI is

Mass of HCl in 1.0 mL stock solution =1.25×29.2100=0.365gMass of HCI required for 200 mL solution of 0.4 M HCI =2001000×0.4×36.5=0.08×36.5g∵0.365g of HCl is present in 1.0mL stock solution. ∴0.08×36.5gHCl will be present in 0.08×36.50.365=8.0mL