Question

In the given reaction:

$3H_{3}P{O}_2\to P{H}_3+2H_{3}P{O}_3$

How many grams of $P{H}_3$ will be formed on a decomposition of 6 moles of $H_{3}P{O}_2$?

• A. $34gm$
• B. $68gm$
• C. $17gm$
• D. $6gm$

Answer 1

The correct option is B $68gm$

The balanced chemical equation is as given below.

$3H_{3}P{O}_2\to P{H}_3+2H_{3}P{O}_3$

3 moles of $3H_{3}P{O}_2$ on decomposition gives one mole of $P{H}_3$.

Thus, 6 moles of $3H_{3}P{O}_2$ on decomposition will give two moles of $P{H}_3$.

The molar mass of $P{H}_3$ is $31+3=34g/mol$.

Hence, the mass of $P{H}_3$ obtained is $2\times 34=68g/mol$.