Question

One of the statements of Dalton’s atomic theory is given below “compounds are formed when atoms of different elements combine in a fixed ratio.” Which law of chemical combination is not related to this statement? (This question has multiple correct options):
A) Law of conservation of mass
B) Law of multiple proportion
C) Avogadro’s law
D) Law of definite proportion

Answer 1

One of the two laws states that under the same conditions of temperature and pressure (or, if remains constant), equal volumes of different gases contain an equal number of molecules. The other law states that the mass of any element at the beginning of any reaction will always remain constant throughout the reaction. These are not related to the statement.

Complete answer:

According to Dalton’s atomic theory, atoms of different elements can join together in fixed, whole number ratios to produce a compound element. Also, the atoms of the same element can join with each other in a different, fixed ratio to form different elements.
This statement describes the law of chemical combination: Law of definite proportion and the law of multiple proportions.
The law of multiple proportions states that when two elements join together to form two or more compounds, the ratios of the masses of one element, which joins with the fixed mass of the other elements are the simple whole numbers.
Again, the law of definite proportions states that a chemical compound always consists of the same elements, combines together in the same proportion by mass.

So, Avogadro's law and the law of conservation of mass is not related to the given statement.

Hence, the correct answer is option A and C.

Additional information:
The postulates of Dalton’s atomic theory are:

1. All the matters in the world, anything it can be, consist of the indivisible particles called an atom.
2. The same element consists of atoms, which are identical in shape, size, forms.
3. Atoms can neither be created nor destroyed.
4. Atoms of different elements can join together in fixed, whole number ratios to produce a compound element.
5. The atoms of the same element can join with each other in different ratios to form different elements.
6. Atoms are the smallest unit that can take part in any chemical reactions.

Note: The Avogadro’s law states that under the same conditions of temperature and pressure (or, if remains constant), equal volumes of different gases contain an equal number of molecules. The law of conservation of mass states that mass is neither created nor destroyed in any chemical reaction. So, the mass of any element at the beginning of any reaction will always remain constant throughout the reaction.