[jumper1127]

The following reaction is at equilibrium at a pressure of 1 atm in a closed container.
NaOH(s)+CO2(g)<-->NaHCO3(s)
Which of the following actions will decrease the concentration of CO2 gas present at equilibrium?
a) adding N2 gas to double the pressure
b) adding more NaOH(s)
c) increasing the volume of the container
d) lowering the temperature
e) all of the above

The answer is d. Could you tell me why a and b are not correct?

It seems that according to ideal gas law, choice a should be wrong, since the gases will not interfere each other. So when we consider a gas, we just need to care about the partial pressure of it?

For choice b, if we add NaOH, the reaction will go left, and there will be less CO2. Why the concentration will not decrease?

[mohd]

because if lower the temperature you will get exothermic reaction , So in exothermic  the reaction will shift to the right to the the product and so that will decrees the co2

[jumper1127]

because if lower the temperature you will get exothermic reaction , So in exothermic  the reaction will shift to the right to the the product and so that will decrees the co2

I know d is right, and I can totally understand it. But why a and b are not correct?

BTW, when can we use concentration=n/V=P/RT to determine the change of concentration?

[mohd]

a ) the pressure will effect the reaction by shifting from high amount of moles to the lower one .

b) the solid will not change their condition during the reaction unless all the reactant and product are solid

[Borek]

because if lower the temperature you will get exothermic reaction

This is completely off and irrelevant. In most cases whether reaction is exothermic or not doesn't depend on the temperature, for sure that's the case here.

[Borek]

a) adding N2 gas to double the pressure
b) adding more NaOH(s)
c) increasing the volume of the container
d) lowering the temperature
e) all of the above

The answer is d. Could you tell me why a and b are not correct?

a - concentration is amount per volume. You increase the total pressure, but amount of CO₂ doesn't change.

b - can you write equilibrium constant? How does it depend on the amount of solids? Does it change just because you have added a soild?