Verified Solution • 2025–26 Session moderate

QJEEM11Ch49ac: JEE Main 2011 Chemistry - Class 11 JEEM11Ch49ac Solution: A vessel at 1000 K contains CO 2 with a pressure of 0.5 atm.…

A vessel at 1000 K contains CO2 with a pressure of 0.5 atm. Some of the CO2 is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0.8 atm, the value of K is :

Multiple Choice Options

  • A 3 atm
  • B 0.3 atm
  • C 0.18 atm
  • D 1.8 atm

Step-by-Step Verified Solution

CO2+C(grapnite) ⇌ 2COC{O_2} + {C_{\left( {grapnite} \right)}}\,\rightleftharpoons\,2CO

Pinitial  0.5atm                       0{P_{initial}}\,\,0.5atm\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0

Pfinal   (0.5−x)atm       2x atm{P_{final}}\,\,\,\left( {0.5 - x} \right)atm\,\,\,\,\,\,\,2x\,atm

Total PP at equilibrium

=0.5−x+2x=0.5+x atm= 0.5 - x + 2x = 0.5 + x\,atm

                       0.8=0.5+x\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0.8 = 0.5 + x

∴\therefore    x=0.8−0.5=0.3 atm\,\,\,x = 0.8 - 0.5 = 0.3\,atm

Now    kp=(PCO)2/PCO2\,\,\,{k_p} = {\left( {{P_{CO}}} \right)^2}/{P_{C{O_2}}}

=(2×0.3)2(0.5−0.3)=(0.6)2(0.2)= {{{{\left( {2 \times 0.3} \right)}^2}} \over {\left( {0.5 - 0.3} \right)}} = {{{{\left( {0.6} \right)}^2}} \over {\left( {0.2} \right)}}

=1.8 atm= 1.8\,atm

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