The following data are obtained when dinitrogen and dioxygen react to gether to form different compounds:
`{:(,,"Mass of dinitrogen",,"Mass of dioxygen"),(i.,,14 g,,16 g),(ii.,,14 g,,32 g),(iii.,,28 g,,32 g),(iv.,,28 g,,80 g):}`
a. Which law of chemical combination is obeyed by the above experimental data? Give its statement.
d. 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

(а) Fixing the mass of dinitrogen as 14 g, the masses of dioxygen combined will be:
`16:32 : 10 : 40`
`2 :4 : 2 :5`
This is a simple whole number ratio and hence, the data illustrate the law of multiple proportions. The law of multiple proportions states that when two elements combine to form two or more than two compounds, then the mass of one of the elements which combine with a fixed mass of the other bear a simple whole number ratio.
(b) (i)
1 km = 1km `xx (1000 m)/(1 km) xx (100 cm)/(1 m) xx (10 mm)/(1 cm) =10^(6)` mm
Convert answer `=10^(6), 10^(15)`
(ii) `1 mg = 1 mg xx (1g)/(1000 mg) xx (1 kg)/(1000 g) = 10^(-6) kg`
1 mg =1 mg `xx (1g)/(1000 mg) xx (1 ng)/(10^(-3)g) = 10^(6)ng`
1 mL `=cm^(3) xx ((1 dm)/(10 cm))^(3) =10^(-3) dm^(3)`
correct answer : `10^(-3), 10^(-3)`