Isotopes of the same element differ only in the number of neutrons an atom has. Its still the same element because the number of protons define an element. Just their neutrons and mass number is different.
Answer:
375 g
Explanation:
Let the total mass of the solution = x g
Given that the mass of NaOH in the solution = 15.0 g
Thus, mass of the solvent = x - 15.0 g
Given that the mass % of the solution = 4 %
So,

So,

<u>Mass of the solution = 375 g</u>
Gives the same result when an experiment is repeated.
A and b is the croccet answer sir hope it helps