Which statement is true of the hydrogenation of benzene?

  the moles   of   sulfuric acid   that are needed to react   completely with 6.4   moles   of lithium hydroxide   is 12.8   moles ( answer a)

calculation

step 1 : write a balanced   chemical equation

2lioh   + h₂so₄   →   li₂so₄   +2h₂o

step 2 : use the mole ratio   to determine   the   moles h₂so₄

from   equation above   lioh: h₂so₄   is 2: 1 therefore   the moles of h₂so₄

= 6.4   x 2/1   = 12.8   moles   of h₂so₄

when the pressure is increased, there will be a shift to the reactants side. decreasing the volume will increase pressure. when you decrease the volume, the gaseous species get more tightly packed of the concentrations of gaseous species increase.

le chatelier's principle says that the system wants to undo this concentration increase so it can decrease pressure.

since the reactants only have 1 mol of gas (only pcl5) and the products have 2 mol of gas (both pcl3 and cl2), it shifts to reactants to decrease concentration, thereby lowering the pressure