Ammonium bromide is a crystalline solid that decomposes endothermically when heated. The reaction is

NH4Br(s) <===> NH3(g) + HBr(g).

When solid ammonium bromide is added to an evacuated flask at 300°C, which change in reaction conditions below will cause the equlibrium to shift to the right?

a. Adding more ammonia
b. Adding more ammonium bromide
c. Lowering the temperature
d. Doubling the volume of the flask
e. None of these

This is my thinking...
a. Incorrect because that would shift it the left
b. Incorrect because adding a solid to an equilibrium wont change it
c. Incorrect because since it is endothermic, lowering the temperature will make it go to the left
d. Increasing the volume won't effect it again because all 3 are not gases

This would leave me with the answer as E... though I thing that is not correct. Are one of my reasonings wrong?

You are correct about a, b, c, and e. The answer is d.
It doesn't matter that all three aren't gases. When the volume of the flask is doubled, the concentration of NH3 and HBr are halved (the solid isn't involved, of course); therefore, the reaction will shift to the right to produce more gases so that K will stay the same. (Otherwise, K would change since concentrations (or partial pressures) change.)

Well well, looks like you've got a brain full of chemistry knowledge! But let me put a twist on things, just for fun.

Indeed, adding more ammonia (a) would make the equilibrium shift to the left, because who wants more gas when we're trying to make a solid disappear, am I right? And adding more ammonium bromide (b) won't change a thing, it's like trying to make a mountain disappear by adding more rocks.

Now, we move on to lowering the temperature (c), which normally would be a great plan to chill out, but in this case, it would actually make the equilibrium shift to the left. It's like telling the reaction to "take a cool break, we don't need more gas right now!"

But when it comes to doubling the volume of the flask (d), oh boy, things get interesting! It might sound counterintuitive, but when the volume increases, those gaseous products will spread out and take up more space. And just like how a clown expands to fill the room, the equilibrium will shift to the right to produce more gas and keep things balanced.

So, to wrap it up, the answer is d, my friend! Double up that flask volume and watch as the reaction dances its way to the right like a clown in a juggling act!

Your reasoning is correct, except for your explanation for choice d. Doubling the volume of the flask will actually cause the equilibrium to shift to the right. When the volume of the flask is increased, the concentration of NH3 and HBr decreases, according to Le Chatelier's principle. To compensate for the decrease in concentration, the equilibrium will shift towards the side with more moles of gas, in this case, towards the right. Therefore, choice d is the correct answer.

Your reasoning for options a, b, c, and e is correct. Adding more ammonia (option a) would shift the equilibrium to the left because it would increase the concentration of NH3 and HBr in the system, causing the reaction to favor the reactants. Adding more ammonium bromide (option b) won't affect the equilibrium because it is a solid and doesn't change its concentration. Lowering the temperature (option c) would shift the equilibrium to the left because the reaction is endothermic, and decreasing the temperature would favor the exothermic direction. Option e is also incorrect as you correctly explained.

However, your reasoning for option d is incorrect. When you double the volume of the flask, the pressure decreases, resulting in an increase in the total moles of gas per unit volume. According to Le Chatelier's principle, the reaction will shift in the direction that produces more gas molecules to restore equilibrium. In this case, increasing the volume will cause the equilibrium to shift to the right to produce more NH3 and HBr gases.

Therefore, the correct answer is d. Doubling the volume of the flask will cause the equilibrium to shift to the right.