Question

How many ml of water should be added to 375ml of a solution containing 0.5g of benzalkonium chloride to make 1 :5000 solution?

Answer 1

1 : 5000 means 1g in 5000 mL of solution

$\frac{1g}{0.5g} = \frac{5000 mL}{ X mL }$

X = 2500 mL of 1 : 5000 of w/v solution containing 0.5 g of benzalkonium chloride

2500 mL - 375 mL = 2125 mL