Answer:
Step-by-step explanation:
We have to make 100 mL 0f .405M HCl from 3 M solution of HCl .
volume of 3M to be taken required . Let this volume be V litre .
V litre of 3M will contain 3 V moles of HCl .
moles contained by 100 mL of ,405 HCl = .405 x .1 = .0405 moles .
So 3V = .0405
V = .0405 / 3 litre
= .0405 x 1000 / 4 mL
= 10.125 mL
So we have to take 10.125 mL of 3M HCl and add water to them to make its volume 100 mL .