Question

With which reference there is no importance of Dalton’s law.
A) Isotope
B) Isobar
C) Iso-osmotic
D) Isothermic

Answer 1

There are different laws of Dalton’s theory you must need to identify which law is asked in the question by looking at the given options. Isobar is a line at a constant pressure and isotherm is a line at a constant temperature.

Complete answer:
We must have knowledge of Dalton’s theory to answer this question. So first let’s learn about Dalton’s atomic law.
Dalton’s atomic theory states that:
All matter consists of indivisible particles called atoms.
Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.
Atoms cannot be created or destroyed.
Atoms of different elements may combine with each other in fixed, simple, whole number ratios to form compound atoms.
Atoms of the same element can combine in more than one ratio to form two or more compounds.
The atom is the smallest unit of matter that can take part in a chemical reaction.
Option A) This option is correct as Dalton postulates says that the mass of all the atoms of the given element is the same. So after the discovery of isotopes the fact that atoms of the same elements can have different masses also due to the presence of different numbers of neutrons in the nuclei.
Representation of an isotope:
$^A{X_Z}$
A: Mass number
Z: Atomic number
Examples of isotopes: $^{35}C{l_{17}}{,^{37}}C{l_{17}}$

Note:
We must remember that isotopes are the species having the same atomic number but different mass number whereas isomers are the molecules having the same molecular formula but different arrangement of atoms in a structure. Dalton’s law states that an atom is the smallest unit of matter that can take part in a chemical reaction.