Question

The thermal stability of hydrides of oxygen family is in order :

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

Answer 1

The correct option is A $H_{2}Po<H_{2}Te<H_{2}Se<H_{2}S<H_{2}O$

As we move down the group, thermal stability decreases (because M-H bond energy decreases), so order is $H_{2}Po<H_{2}Te<H_{2}Se<H_{2}S<H_{2}O$.