Question

Exercise 15.75 by the following exothermic reaction Coal, which is primary carbon, can be converted to natural gas, primarily CH C(s) + 2H; () CH,() Part A If this reaction mixture is at equilibrium predict the effect of the following Drag the appropriate items to their respective bins. Reset Help lowering the volume of the reaction modure adding more to the reaction mature adding a catalyst to the reaction mixture raising the temperature of the reaction adding more H, to the reaction Shift right No effect in 2e e IM

Answer 1

Answer :

The given exothermic reaction is -

C_(s) + 2H_2(g)  $\rightleftharpoons$ CH_{4 (g)}     ;
ΔΗ = (-ve

As the reaction is exothermic that is why the $\Delta H$ value is negative. That means heat is realesed during the forward reaction.

It is given that the reaction is in a equilibrium. So if we make any external change on the reaction condition then the equilibrium of the reaction of the reactant will be distrubed then according to the Le Chatelier's Principle the reaction will shift its equilibrium position(either right or left) in the direction where those external change will compensate.

1.

If we lower the volume of the reaction mixture then the number of the molecule per unit volume will increases i.e. concentration will increases . So the reaction will try to decrease its concentration . For this purpose the reaction will shift in that direction where the mole number is decreasing. From the equation it is clear that for the forward reaction, product mole number is 1 and reactant mole nomber is 2 ( only gaseous reactant and product is to be considerd), that means the forward reaction is occurring with decrement of mole number. That is why the reaction will occurs more in the forward derection(i.e. right side) than the backward direction (left shift)

So on lowering the volume of the rraction muxture the equilibrium of the reaction will shift right side.(i.e. forward direction)

Therefore  Right Shift.

2.

If we add more C to reaction mixture then the raction will try to decrease the concentration of C. For this, the reaction have to go more in forward direction which will decrease the concentration of the reactant C . That means the equilibrium will shift in the right direction (forward direction)

Therefore Right shift.

3.

If we add a catalyst there will be no change in the position of the equilibrium because catalyst will increase the rate of both forward and reverse reaction with same extent. Catalys just help to get the equilibrium fast but no effect in the position of the equilibrium.

So there is no effect on reaction equilibrium by adding a catalyst.

4.

The above reaction is a exothermic reaction (given). So heat is released during the forward reaction. So if we increase the temperature of the reaction then the rate of tge forward reaction will be decrease to compensate the effect of increasing temperature. That means the equilibrium will shift in the reverse direction i.e left shift.

Therefore  left shift occurs when temperature is increses.

5.

If we add more H₂(g) to the reaction mixture then the reaction will try to decrease the concentration of the H₂(g)  to compensate the effect of extra addition. So Extra H₂ will react with C to form more CH_{4^{​​​​​​}}   i.e. Rate of forward reaction increases. That means the equilibrium will shift towards Right Side.

Therefore right Shift occurs.

(Answered)