Question

The number of water molecules differing in molecular mass formed by hydrogen isotopes and ${}^{1}H,{}^{2}H,{}^{3}H$ and oxygen isotopes ${}^{16}O,{}^{17}O,{}^{18}O$ is _________________.

• A. $6$
• B. $9$
• C. $12$
• D. $18$

Answer 1

The correct option is A $6$

Water molecule mass formed by $O^{16}$ and $H^1,H^2,H^3$ isotope is 18,20,22,19,20,19,21,20,21

Water molecule mass formed by $O^{17}$ and $H^1,H^2,H^3$ isotope is 19,21,23,20,21,20,22,21,22

Water molecule mass formed by $O^{18}$ and $H^1,H^2,H^3$ isotope is 20,22,24,21,22,21,23,22,23

There are total 6 different water molecules can be formed which have mass 18,19,20,21,22,23.