Question

Law of Reciprocal proportions

Answer 1

law of reciprocal proportion :- when two elements combine with fixed weight of third elements , then it is either the same or simple multiple ratio of weight of two elements which combine directly with each other .

example :- take three elements C , O and S
C and O combine to form CO and CO2
so, ratio of O in CO and CO2 = 1 :2
e.g simple ratio.

now,
C and S combine to form , CS2
so, ratio of C and S = 12 : 64 = 3 : 16
e.g simple multiple ratio
so, All elements C , O, and S form compound and follow law of reciprocal proportion .

Answer 2

By definition, the law is: the relative weights in which two substances form a chemical union singly with a third are the same as, or simple multiples of, those in which they unite with each other.
SO, the third element here is carbon, so by the law, knowing how oxygen bonds with carbon and how hydrogen bonds with carbon should tell us how hydrogen bonds with oxygen.

So: (% Hydrogen in Methane) / (% Oxygen in Carbon Dioxide)
or 25/72.73 = .343

*should equal*

(multiple of % Hydrogen in Water) / (multiple of % Oxygen in Water)

so X*(11.1) / (88.9) needs to equal .343

Solved, X= 11/4

So the 11 times the % Hydrogen in Water / 4 times the % Oxygen in Water is the same proportion as these molecules individually combine with carbon.

Hope this helps!