chemistry alevel

Alkenes react with hydrogen gas in the presence of a nickel catalyst.
0.2 mol of an alkene reacted completely with 19.2 dm3
of hydrogen gas at room
temperature and pressure.
How many C C bonds are there in a molecule of this alkene?
[The molar volume of a gas is 24.0 dm3
mol–1 at room temperature and pressure]
A 4
B 3
C 2
D 1
can someone explain this

How many mol is 18.2 dm3? What is the ratio of alkene : H2?

idk there is no ratio and the equation is not given

How many mol is 18.2 dm3 of any gas at RTP?

0.7583

My most sincere apologies, I am recovering from a migraine, I mistyped your original Q.

How many mol is 19.2 dm3 of any gas at RTP? 0.8 mol. I give you the answer to that, since 18.2 does give you 0.758.

So... 0.2 mol of the alkene reacts with 0.8 mol of H2.

Well, if the alkene had 1 double bond, it would need 1 H2 to hydrogenate that double bond. So... how many double bonds does the alkene in this Q have?

4 right ? because there is 0.8 mol of hydrogen ? and 0.2 mol of hydrogen would make 1 double bond is that right ?