Question

If the atomic weight of oxygen were taken as $90$, then what would be the molecular weight of water?

• A. $101.25$
• B. $104.52$
• C. $112.5$
• D. $142.5$

Answer 1

Answer: (A)

$101.25$

If the atomic weight of oxygen = $90g$.
Then the factor by which oxygens atomic mass changes is, $\frac{90}{16}=5.62$

If we go with the same assumption then the mass of hydrogen will also get change by the same factor. So, a new mass of two hydrogen atoms will be,

$5.62\times 2=11.24g$

now, a total mass of water would be, $90+11.24=101.25g$

Hence, the correct option is (A).