BMAT chemistry past paper Q

A mixture of C2H4(g) and H2(g) is placed in a sealed container. Some finely divided nickel is
added as a catalyst to the mixture. The temperature rises to 150°C and the two gases slowly
react to give C2H6(g).
Which row of the table correctly identifies how the pressure changes after the nickel is added?

why did the pressure increase before adding a catalyst?

Reply 1

ambot

Original post by yousefsharayah

''A mixture of C2H4(g) and H2(g) is placed in a sealed container. Some finely divided nickel is
added as a catalyst to the mixture. The temperature rises to 150°C and the two gases slowly
react to give C2H6(g).
Which row of the table correctly identifies how the pressure changes after the nickel is added?''

The question suggests that the temperature rises to 150 after the nickel is added. therefore initially the pressure will increase since the temperature has increased. however as the reaction proceeds the pressure decreases because the products have less gaseous moles than the reactants (1:2).