Question

Which of the following is not poisonous?

• A. $H_{2}O$
• B. $H_{2}S$
• C. $H_{2}Se$
• D. $H_{2}Te$

Answer 1

The correct option is A $H_{2}O$

The hydride of oxygen, i.e., $H_{2}O$ is a colourless, odourless liquid while the hydrides of all the other group $16$ elements are unpleasant, foul smelling, poisonous gases. $H_{2}O$ has the highest boiling point of $373K$ amongst the hydrides of group $16$ elements.