2. structure of atom — Chemistry STD 11 Science — Question

$2 Cu ( s )+ H _2 O ( g ) \longrightarrow Cu _2 O ( s )+ H _2( g )$

$P _{ H _2}$ is the minimum partial pressure of $H _2$ (in bar) needed to prevent the oxidation at $1250 K$. The value of $\ln \left( p _{ H _2}\right)$ is. . . . .

(Given: total pressure $=1$ bar, $R$ (universal gas constant) $=8 JK ^{-1} mol ^{-1}, \ln (10)=2.3$. $Cu ( s )$ and $Cu _2 O ( s )$ are mutually immiscible.

At $1250 K : 2 Cu ( s )+1 / 2 O _2( g ) \longrightarrow Cu _2 O ( s ) ; \Delta G ^\theta=-78,000 J mol ^{-1}$

$H _2( g )+1 / 2 O _2( g ) \longrightarrow H _2 O ( g ) ; \Delta G ^\theta=-1,78,000 J mol ^{-1} ; G$ is the Gibbs energy)

$(A)$ Emit or absorb energy in the form of electromagnetic radiation

$(B)$ Frequency distribution of the emitted radiation depends on temperature

$(C)$ At a given temperature, intensity vs frequency curve passes through a maximum value

$(D)$ The maximum of the intensity vs frequency curve is at a higher frequency at higher temperature compared to that at lower temperature