Question

A mixture of $2$ mole of $CO$ and $1 mol$ of $O _{2}$ is ignited. Correct relationship is

• A. $\Delta H =\Delta U$
• B. $\Delta H >\Delta U$
• C. $\Delta H <\Delta U$
• D. The relationship depends upon the capacity of vessel

Answer 1

Answer: (C)

$2 CO ( g )+ O _{2}( g ) \longrightarrow 2 CO _{2}( g )$
$\Delta n _{9}=2-3=-1$
We know,
$\Delta H=\Delta U+\Delta n_{g} R T $
$\Delta H=\Delta U-1 \times R T$
$\Rightarrow \Delta H=\Delta U-R T $
$\Rightarrow \Delta H < \Delta U$
$[8 = 10 - 2 \Rightarrow 8 < 10]$