Fill in the blanks in the following conversions :
(i) 1 km =.........mm =.........pm
(ii) 1 mg =.........kg =.........ng .
(iii) 1 mL =.........L =.........`dm^3`

Explanation

(a) If the mass of dinitrogen is fixed to 28 g, the masses of dioxygen combined in the four cases will be 32 g, 64 g, 32 g and 80 g respectively which are in the ratio `2:4:2:5` which is a simple whole number ratio. Hence, the given data obey the law of multiple proportions. For definition, see the text.
(b) (i) `1 km = 1 km xx (1000 m)/(1 km) xx (100 cm)/(1 m) xx (10 mm)/(1 cm) = 10^(6) mm`
`1 km = 1 km xx (1000 m)/(1 km) xx (1 "pm")/(10^(-12) m) = 10^(15) "pm"`
(ii) `1 mg = 1 mg xx (1 g)/(1000 mg) xx (1 kg)/(1000 g) = 10^(-6) kg`
`1 mg = 1 mg xx (1 g)/(1000 mg) xx (1 ng)/(10^(-6) g) = 10^(6) ng`
(iii) `1 mL = 1 mL xx (1 L)/(1000 mL) = 10^(-3) L`
`1 mL = 1 cm^(3) = 1cm^(3) xx (1 dm)/(10 cm) xx (1 dm)/(10 cm) xx (1 dm)/(10 cm) = 10^(-3) dm^(3)`