## The following data are obtained when dinitrogen and dioxygen react together to form different compounds

### Q.21:- The following data are obtained when dinitrogen and dioxygen react together 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. (b) Fill in the blanks in the following conversions: (i) 1 km = …………………. mm = …………………. pm (ii) 1 mg = …………………. kg = …………………. ng (iii) 1 mL = …………………. L = …………………. dm3

Answer:-
(a) Fixing the mass of dinitrogen as 28 g, masses of dioxygen combined will be 32, 64, 32 and 80 g in the given four oxides. These masses of dioxygen bears a simple whole number ratio as 2:4:2:5. Hence, the data given will obey the law of multiple proportions.
The statement is as follows two elements always combine in  a fixed mass of other bearing a simple ratio to another to form two or more chemical compounds.
(b) (i) 1 km =  1km×1000m/1km×100cm/1m/10mm/1cm = 10mm
1 km =  1km×1000m/1km×1pm/10-12m = 1015 pm
(ii) 1 mg = 1mg×1g/1000mg×1kg/1000g = 10-6 kg
1 mg = 1mg×1g/1000mg×1ng/10-9g = 10-6 ng
(iii) 1 mL = 1mL×1L/1000mL = 10-3 L
1 mL = 1cm3 = 1cm3×(1dm×1dm×1dm/10cm×10cm×10cm) = 103dm3