An optically active alkyne A (C10H14) can be catalytically hydrogenated to butylcyclohexane. Treatment of A with C2H5MgBr liberates no gas. Catalytic hydrogenation of A over Pd/C in the presence of quinoline poison and treatment of the product B with O3 and then H2O2 gives an optically active tricarboxylic acid C8H12O6. (A tricarboxylic acid is a compound with three –CO2H groups.) Give the structure of A (without stereochemistry).

The reverse process, hydrogenation, can be performed in the presence of a catalyst like metallic platinum. Hydrogen gas reacts with the metal surface, breaking the hydrogen-hydrogen bond to form weaker metal-hydrogen bonds. An alkene or alkyne can then react with the metal in a similar manner, then form stronger bonds with two or more hydrogen

Explanation:

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

1.solid

2.carbon dioxide

3.helium