Question

Oxygen and sulphur both are the member of same group in periodic table but $H_{2}O$ is liquid while $H_{2}S$ is gas because

• A. molecular weight of water is more
• B. electronegativity of sulphur is more
• C. $H_{2}S$ is weak acid
• D. water molecules are having weak hydrogen bonds between them

Answer 1

Answer: (D)

Due to the presence of hydrogen bonding the molecules of the compound associated together
Both $O$ and $S$ belong to the same group but $H_{2}O$ is a liquid while $H_{2}S$ is a gas. This can be explained on the basis of electronegativity. In water due to the high electronegativity of oxygen, hydrogen bonds are formed. As a result the molecules of $H_{2}O$ get associated together, hence water exists as a liquid at room temperature. On the other hand, the electronegativity of $S$ is less and therefore, hydrogen bonding in $H_{2}S$ is almost negligible. As a result of which molecules of $H_{2}S$ are not associated and $H_{2}S$ exists as a gas at room temperature