What is mass of 3.5 moles of LiOH?

Option B.

Explanation:

Isotopy is a phenomenon where by two or more atoms have the same atomic number (proton) but different mass number due to the difference in neutron present in the atoms. The atoms that exhibit Isotopy are isotopes.

With the above information, we can obtain the right answer to the question given above as follow:

For option A:

Isotope >> atomic no >> Mass no

16 8X >>> 8 >>>>>>>>> 16

16 6X >>> 6 >>>>>>>>> 16

Since they have the different atomic number, they are not isotope.

For option B:

Isotope >> atomic no >> Mass no

16 8X >>> 8 >>>>>>>>> 16

17 8X >>> 8 >>>>>>>>> 17

Since they have the same atomic number but different mass number, they are isotope.

For option C:

Isotope >> atomic no >> Mass no

12 6X >>> 6 >>>>>>>>> 12

14 7X >>> 7 >>>>>>>>> 14

Since they have different atomic number, they are not isotope.

For option D:

Isotope >> atomic no >> Mass no

6 26X >> 26 >>>>>>>>> 6

26 6X >>> 6 >>>>>>>>> 26

Since they have different atomic number, they are not isotope.

From the above illustration, only option B contains isotopes because the atoms have the same atomic number but different mass number