Question

The ratio of $\mathrm{H}:\mathrm{O}$ by mass in water is

• A. 1:8
• B. 8:1
• C. 2:1
• D. 1:2

Answer 1

The correct option is A

1:8

Explanation:

• The molecular formula of water is ${\mathrm{H}}_2\mathrm{O}$
• In ${\mathrm{H}}_2\mathrm{O}$, there are two atoms of hydrogen and one atom of oxygen.
• Mass of hydrogen atoms in water $=2\times 1=2\mathrm{u}$.
• Mass of oxygen atom in water$=16\mathrm{u}$
• The ratio of hydrogen to oxygen in water$=2:16=1:8$

Therefore, option (A) is the correct answer. The ratio of $\mathrm{H}:\mathrm{O}$ by mass in water is $1:8$.