The anode rays (positive rays) obtained from _______ gas, consists of only protons.
Hydrogen gas (H2) produces positive rays which only consists of protons.
As electrons are knocked out of Hydrogen atoms in the discharge tube, positively charged ion of Hydrogen is produced that only consists of one proton. Therefore, Hydrogen gas produces positive rays which only consists of protons.
Hence, the anode rays (positive rays) obtained from hydrogen gas, consists of only protons.