Question

A sample of pure water , irrespective of source ,contains 88.89{\raise0.5ex\hbox{\scriptstyle 0} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 0}} oxygen and 11.11{\raise0.5ex\hbox{\scriptstyle 0} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 0}} hydrogen by mass. The data supports the :
A . Law of conservation of mass
B . law of constant composition
C . law of multiple proportion
D . law of reciprocal proportion

Answer 1

Hint: First of all we should be familiar with all the four options .lets start with the Law of conservation of mass which states that ‘’Mass is neither created nor destroyed in ordinary chemical and physical changes”. Also take a look at the rest of the Laws.

Complete step by step solution:
Law of constant composition -A compound contains elements in a certain fixed proportions and in no other combination , regardless of how the compound is prepared or where it is found in nature.
Law of multiple proportion – When two elements from a series of compounds, the ratio of the masses of the 2nd element that combine with 1 gram of the first element can always be reduced to small whole numbers.
Law of reciprocal proportion -If two different elements combine separately with the same weight of 3rd element ,the ratio of the masses in which they do so are either the same or a simple multiple of the mass ratio in which they combine.
Water molecule is made up of 2 hydrogen atom of relative mass 1 and oxygen of relative mass 16.So the ratio in which the both atom combined to form water is 1:8 so it is clearly following the law of constant composition in this problem because it is given that a sample of pure water, irrespective of source, contains 88.89{\raise0.5ex\hbox{\scriptstyle 0} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 0}} oxygen and 11.11{\raise0.5ex\hbox{\scriptstyle 0} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{\scriptstyle 0}} hydrogen by mass which is in ratio of 1:8.

Note: We have solved this problem by taking the ratio of hydrogen and oxygen and we get that the atoms are combined in a ratio nearly 1:8. It is also given in the problem that it is irrespective of source. So the data supports the law of constant composition.