[ktgerloff]

Hello,

This problem is from a practice exam from my second term general chemistry class. The correct answer is highlighted in red:

When 1.13 g of V is dissolved in HCl, 0.08888 g of hydrogen gas is produced.  Determine the value of x in the compound, VClx, produced according to the following equation:

V  + xHCl  →  VCl_x  +  (x/2) H2

a) 1
b) 2
c) 3
d) 4
e) none of these

I see how all of these answers will balance the equation. I must be missing the point of the question here. Can someone please explain what I am missing?

[Corribus]

There may be many ways to correctly balance the equation, but only one of them will work with the masses of reagents and products provided. A hint is to convert those masses into moles and then consider the stoichiometry.

[ktgerloff]

I see, so there is 0.022 mol V and 0.044 mol H₂.

So, for every 1 mol of V, there must be 2 mol of H₂.

Which is where the 4 comes from...

Thanks!