Does this show that hydrogen is still present? Here is the procedure:?

Question

Place pieces of mossy zinc (about 5g) in the erlenmeyer flask. Add 2 ml of copper (II) sulfate solution through the thistle tube. make sure all the connections are air tight. Put 3 test tubes filled with water to collect gas. Provide the test tubes with stopper. Pour 6N HCl through the thistle tube until the zinc is covered. If the reaction becomes sluggish, add more acid. Collect three test tubes of the gas Stopper the test tubes tightly under water and place them in the rack with their mouths downwards. Wash the remaining mossy zinc and return it to the stockroom.

Answer 1

This sounds like a standard laboratory experiment to produce 3 test-tubes of hydrogen gas, and not to waste any zinc when the experiment is over. The copper sulphate is a catalyst. The HCl would have been in excess, so the unreacted zinc is removed and washed to stop the reaction.